This character sheet is for the [[LongRunners long-running]] MedicalDrama ''Series/{{ER}}''. ''Warning! Major spoilers ahead.''
%% Per wiki policy, name of the trope should never be spoiler-tagged on character sheets.


[[folder: Mark Greene]]
!'''Mark Greene'''
->'''Played By''': Anthony Edwards

* AmbiguouslyJewish: One of his parents was Jewish and he knows a bit of Yiddish and some Jewish prayer. Other than that, he doesn't display any Jewish mannerisms and Anthony Edwards himself is not Jewish.
** Greene actually describes himself as the son of "a lapsed Catholic and an agnostic Jew."
* BackForTheFinale: While he doesn't appear in the final episode, a flashback episode midway through the last season showing Catherine Banfield's first encounter with County Hospital reveals that Greene treated her son (sadly, the son was already terminally ill). The event clearly takes place shortly before his death, which adds a further bit of melancholy.
* BadassBeard: Grew one at least twice. The first time, in season 2, it was to impress women (Mark also tried wearing contacts). The second time he grew one when [[BeardOfSorrow his mother was hospitalised]].
* BetaCouple: Mark and Elizabeth's relationship has aspects of this--they don't get together until after Doug leaves and the writers clearly needed a couple to replace Doug and Carol. While it is at the forefront (mainly because Mark was the de facto main character), their relationship is relatively problem free and problems only really arise when Elizabeth gives birth and Rachel comes to live with them.
* BettyAndVeronica: For Mark it seems to be Susan and Jen and eventually Susan and Elizabeth.
* BirdsOfAFeather: Mark and Susan.
* BittersweetEnding:[[spoiler: Despite dying of cancer, in the very least he got to spend his last moments with his family and in an island paradise]].
* BookEnds: When his father died Mark spent his last days repairing their relationship. When he was dying he pulled Rachel out of school so that he could spend his last moments with her and try to repair their relationship.
* ButtMonkey: 8 seasons, and something crappy happened to him in every one of them.
* TheCasanova/ CasanovaWannabe: Amazingly, despite never having slept with anyone other than his wife, Mark manages to pick it up after his divorce and Susan's leaving. Unfortunately he's not so good at the finer aspects of being a player, scheduling three dates on the same night that all the participants find out about (Nina, the psych attending, eventually agrees to go out with him).
* ChronicBackstabbingDisorder: His position of authority puts him in difficult standing with his friends, and often times had to make tough choices involving them. He rarely, if ever, outright stabbed anyone in the back, unlike Kerry.
* DeadpanSnarker: Develops quite a sense of humour when he was diagnosed with a brain tumour.
* GenerationXerox: [[spoiler:His daughter followed his footsteps and applies to medical school in the GrandFinale.]]
* TheHero
* TheHeroDies
* HeroicBSOD: He suffers these repeatedly--after mishandling a childbirth, resulting in the mother's death, after his wife leaves him for another man, after Susan leaves him before they can even have a relationship, after being beaten up (losing Susan made him feel bad, being beaten up made him feel worse), a small one after his father dies and after learning that his brain tumor has returned and is now inoperable.
* HeterosexualLifePartner: With Doug. Their friendship is complicated by Mark's role as an authority figure and his boss.
* HollywoodAtheist: In one deleted scene from ''On The Beach'', Mark says outright that he doesn't believe in God.
* {{Hypocrite}}: Frequently chastised Doug for getting too personally involved with cases and bending/breaking the rules to help his patients when he himself often did the same thing.
** Blasted Kerry for not wanting to report her Alzheimer's stricken mentor. A year later, when he himself suffered cognitive impairment following brain surgery and chemotherapy, blasted Kerry for reporting ''him''.
* IllBoy
* IWantMyBelovedToBeHappy: In a deleted scene for ''On The Beach'', Mark tells Elizabeth he has absolutely no problem with the idea of her getting re-married again, saying that she deserves to be happy and that Ella deserves a father. Elizabeth is very resistant to the idea and tells Mark he should stop talking this way.
* IWasQuiteALooker: The, now balding, Mark tells Rachel that he used to have hair down to his shoulders. Anyone who's seen Anthony Edwards in [[Film/FastTimesAtRidgemontHigh Fast Times]] can vouch for this.
* MagneticHero: Is ''very'' respected by his colleagues. Even [[IWorkAlone lone wolf]] Benton sometimes goes to Mark for advice. Works posthumously too, Banfield agrees to give Carter work in the ER whilst he's in Chicago because she learned that Mark was one of his teachers (Mark treated her son).
* MeaningfulName: Green is the color of medicine.
* OppositesAttract: Mark and Elizabeth show shades of this. While they get along very well their personalities are quite different. Mark is rather soft and more patient, more willing to understand people and to give them second chances. Elizabeth is a lot tougher and a lot harsher. Their respective personality differences become apparent when Ella overdoses on Rachel's ecstasy, Elizabeth wants Mark to call the police and wants Rachel out of the house (and tells her as much), whereas Mark (probably because Rachel is his daughter) just wants to work things out and to try and help his daughter. Elizabeth is also more career-oriented, taking up Romano's offer of the Associate Chief of Surgery position despite suspecting ulterior motives, whereas Mark is content just to run the ER.
* ParentalNeglect: Claims that, as a teenager, he started acting out in frustration because his father was never around. Mark starts to fear, even before his tumour recurs, that Rachel's acting out is because he made the same mistakes.
* ParentalSubstitute: For Carter. Mark gives Carter the nurturing encouragement that he doesn't get from Benton, and they fill a need in each other's lives, as Mark doesn't get to see his daughter very often and Carter's parents are often on vacation somewhere.
* PosthumousCharacter: ''On The Beach'' is somewhat non-linear, in that it aired after ''The Letter'', in which the ER staff are notified that he has died, and yet it takes place immediately after ''Orion In The Sky'' (Mark's last day), during ''Brothers and Sisters'' (Elizabeth goes to Hawaii to be with Mark) and between ''The Letter'' (Mark's death obviously happened before the episode, but Mark's funeral happened afterwards). Meanwhile, the final season episode that featured his "return" was actually a flashback to his last days at the hospital.
* TeamDad
* TookALevelInJerkass: Starting in Season 3 after Susan leaves, beginning with him violating Jeanie's privacy by snooping into her files to find out her HIV status. It kicks into high gear after he's beaten up--he becomes cynical and unpleasant and while arguably he deals with some patients the way they should be dealt with,most of the time he just comes off as a total jerk. It doesn't last.
** After his first tumour, Mark begins to suffer personality changes. While not as bad as when he got beaten up, Susan reprimands him at one point for being so harsh with patients and tells him that he isn't quite the kind and caring Mark Greene she used to know.
* UnresolvedSexualTension: With Susan, ultimately leading to an averted RaceForYourLove scenario.
** A deleted scene from ''Orion In The Sky'' (Mark's last day at County) has Mark and Susan talking about what happened at Union Station five years later. Susan obliquely asks Mark if she hadn't moved away, they'd be together. Mark then mentions his grandfather and how he used to say that everything happens for a reason, then he says it was just one of those things that sounded even stupider as he got older.
* VigilanteExecution: He not only refused to help the man who threatened to kill him and his family, he taunted him as he died by holding up the shock paddles in front him. He never suffered any legal ramifications for doing so.
* YankTheDogsChain: Anspaugh, at one point, promises to offer Mark a tenured position at the hospital within three years if he agrees to stay on staff and not join a NASA program. This means that Mark could get tenure as early as 2002. Mark died in 2002.
* YourDaysAreNumbered

[[folder: Doug Ross]]
!'''Doug Ross'''
->'''Played By''': Creator/GeorgeClooney

* AbusiveParents: A BerserkButton for him, no doubt because his father was one of these.
* BreakoutCharacter
* BrokenPedestal: Becomes this to the son of a woman he dates in Season 1 after he inevitably cheats on her and ruins the relationship.
* CallingTheOldManOut: Does a great version of this with abusive father when he blasts him for his horrible childhood, but inverted by his father when he tries to blame him for his horrible adulthood, who informs him that [[JerkassHasAPoint "You're 34 years old. How you live your life is your decision."]]
* TheCasanova
* ChickMagnet
* ChuckCunninghamSyndrome: In the first season, it's mentioned at least twice that he has a son. Scant details are given about this except the child's age--8--and that he doesn't even know the boy's name. This is never mentioned again throughout the rest of his time on the show, not even during key storylines where it would make sense--his abusive father resurfacing and later dying, his and Carol's decision to have a baby. At one point, when a character asks if he has any kids, he says "no".
** Doug himself doesn't appear at Mark's funeral--without any explanation as to why--even though they were best friends. He and Carol also didn't appear at his wedding to Elizabeth, although that can be explained away (a storm essentially grounded all of Mark and Elizabeth's out-of-state guests, including Rachel).
* DisappearedDad: Had one, may have been one to the above mentioned son.
* FreudianExcuse: His experiences with an abusive father explains much of his behavior, bad ''and'' good.
* FriendToAllChildren: Consistently.
* FunctionalAddict: While he clearly has a drinking problem-he shows up drunk at the hospital in the pilot episode and Mark's reaction indicates that this isn't the first time this has happened--it never seems to affect his work or cause any other mishaps for him. Even when he gets his act together he never declares himself to be an alcoholic and given that he seems less inclined to drink when things are going well for him, he may just be very inclined to DrowningMySorrows.
* HeelRealization[=/=]HeroicBSOD: After one of his random one-night-stands dies of an overdose and it really begins to sink in just how much he's screwed up his life.
* HeterosexualLifePartners: Mark and Doug are best friends, and seem to spend a lot of time together. As Doug is such a 'cowboy' (as some of the other doctors put it) Mark's position of authority often complicates their friendship. However Mark, more often than not, is perfectly willing to advocate for Doug and during season 2 campaigns to keep him at the hospital despite the fact that the Pediatric Chief Attending wants him gone, stating that he's a good doctor.
* HollywoodAtheist: Claims to be 'Pagan' but demonstrates contempt for religion (specifically Christianity). He crosses himself in one episode which suggests he may have grown up Catholic, only to lose his faith later on.
* LadykillerInLove: He's established as the hospital stud in his very first episode. But in that same episode, it's also poignantly obvious that he's desperately in love in Carol.
* TheLancer
* MrFanservice
* OfficialCouple: With Carol. (For their time on the show, anyway). In the episode that featured their return, we see that this has advanced to HappilyMarried.
* OneTrueLove: Carol. Doug mentions to Mark when they got back together that his relationship with Carol was the only one that felt "right". In a Season 1 episode, even his current girlfriend notes this.
* PutOnABus
** TheBusCameBack: Twice. Once for a cameo in season six, the second time in season 15.
* ReallyGetsAround: Until the third season, where Doug tries and succeeds in changing his ways.
* ScrewTheRulesImDoingWhatsRight: Deconstructed. This was essentially his motto but ultimately became his downfall when actions ended up jeopardizing the careers of himself and others.
* SexGod: Dialogue from current and former girlfriends make it quite clear he's this.
* TroubledButCute
* TheUnseen: Doug is mentioned as having come to Chicago to see his daughters and Carol at least once during season 6, but the viewer doesn't see his visit or his and Carol's exchange.

[[folder: Susan Lewis]]
!'''Susan Lewis'''
->'''Played By''': Sherry Stringfield

* CharacterSignatureSong: "Blackbird" by Music/TheBeatles. In season 2 this trope is very much played for drama as the song becomes symbolic of the bond between her and her niece Little Suzy.
* ChastityCouple: With Carter. Susan mentions in ''Secrets and Lies'' that they had yet to have sex, and she breaks up with him after realizing that he was obsessed with Abby and didn't feel that way about her.
* FoolishSiblingResponsibleSibling: Was the latter to her drug-addicted older sister.
* HairOfGoldHeartOfGold: Dark blonde rather, but the trope still applies.
* HeroicBSOD: Had to see a therapist after she was forced to give her niece (who she was raising as her own daughter) back to her sister. In an earlier season, she also struggles with confidence issues after being blamed for a patient's death.
* NoodleIncident: After her return. It seems like the viewer missed a few things, including her engagement to a real-life cowboy.
* ParentalNeglect: Her mother is rather aloof and self-absorbed and it's implied that Susan and her sister pretty much had to take care of themselves growing up, leading to the latter's problems. Her father initially doesn't seem to be much better, although he eventually steps up and offers to take care of little Susie at night whilst Susan goes to work.
* PutOnABus: After seasons 2 and 11.
** TheBusCameBack: Returned as a regular in season 8 and stayed until season 12. She also came BackForTheFinale.
* TheUnfavorite: Was also inexplicably this to her drug-addicted older sister, despite being a doctor. To their credit, as cited above, after her sister abandons the baby, their parents realize their mistake and pitch in to help.
* UnresolvedSexualTension: With Mark. According to Carol, Susan absolutely wanted Mark to come to Maui with her, but was afraid that he would be freaked out by the invitation. When he gets sick Susan takes care of him, which makes Carter (who didn't know Mark was sick again) rather jealous.
** Some with Carter, when she left the first time. When she comes back, they get together but the relationship more-or-less fizzles because of Carter's obsession with Abby.

[[folder: John Carter]]
!'''John Carter'''
->'''Played By''': Creator/NoahWyle

* AbusiveParents: Of the severely emotionally neglectful type, to the point where not even him being nearly ''stabbed to death'' could make them cut short their vacation plans to be by his side. However, their FreudianExcuse of their grief for his younger brother makes them slightly more sympathetic than most examples of this trope.
* AudienceSurrogate: Started out as this, being the only rookie among the more experienced staff.
* BreakoutCharacter: Was generally quite a popular character throughout the show. Helped largely by his relative affability, his natural development, and overall longevity. Noah Wyle received more Emmy nominations than any member of the cast outside of Julianna Margulies.
* ButtMonkey: He suffers through a lot of pain and humiliation. Some of it is PlayedForLaughs, but there are also a fair number of darker moments that take a toll on him (see HeroicBSOD).
* TheCasanova: Carter's pretty much able to get any girl he wants, although he rarely seems to use this ability, instead going for the 'maybe we should be friends first' approach.
* CharacterDevelopment: As prominent an example as the show could give. He starts out the first few seasons as a TagalongKid, learning how to function in the hospital setting under Peter Benton's tutelage while also figuring out what role he wants to play as a doctor (eventually switching from surgery to emergency medicine). He then grows comfortable at County, gradually settling into the role of TheLancer for Mark Greene (especially after Doug Ross leaves Chicago). When both Greene and Benton vacate during Season 8, it is explicitly noted that he has become TheHero, a role that he carries throughout the remainder of his time on the show. By the time he is ready to leave, it is clear that the rest of the staff thinks of him as the BigGood, something made more apparent when he returns in Season 15 and a delighted Archie Morris explains to Catherine Banfield that he's a legend.
* ChickMagnet: How many girlfriends did he have during the entire show, again?
* DramaticallyMissingThePoint: When some of the hospital staff stage an intervention against Carter he challenges them to name one instance of him endangering patients' lives. Jing-Mei mentions how he sent a patient into anaphylactic shock by giving her a drug she told him she was allergic to. Carter then retorts that she almost killed a man by leaving a guide wire in his chest. Firstly, said incident took place practically six years ago, when Chen was a med student. Secondly, that incident was no indicator that Chen was starting to fall apart.
* HeroicBSOD: Carter goes through a lot of trauma on the show, like most main cast members. The fact that he was the longest-running character meant that they were even more frequent, especially as it resulted in him seeing friends and family die around him. They include:
** The death of his friend Dennis Gant in Season 3 (heavily implied to be suicide due to Benton's rigid treatment of him). Carter spends much of the following episode going over how much more supportive he could have been when it was clear that Gant was struggling.
** The murder of Lucy Knight. The ER had admitted a schizophrenic patient that Lucy had expressed concern over, only for Carter to brush her off. The patient then ended up stabbing them both, with Carter eventually surviving while Lucy succumbed to complications in surgery. The aftermath provides enough trauma to send Carter over the edge and into drug addiction.
** The death of his grandmother in Season 9. As he was dating Abby Lockhart at the time, the issue becomes exacerbated when Abby has to help take care of her bipolar brother Eric (who shows up uninvited to the funeral and falls into the open grave). This leads to Carter feeling alone in his time of grief and partially results in his decision to join Luka in the Congo.
** The stillborn birth of his son in Season 10 crushes Carter immensely (he is shown breaking down in his father's arms immediately afterward) and casts a huge shadow on his relationship with Kem. Even by the time of the series finale 5 years later, it's left ambiguous as to whether or not their relationship can fully recover.
* {{Hypocrite}}: Lectures Lucy about taking amphetamines for [=ADHD=], as it's typically a pediatric illness and she's in her early 20s. She irritatedly tells him that he's not her physician and that it isn't any of his business. A year later, when Mark asks him what pain medication he's on, he gives a similar answer. So it's okay for him to butt into Lucy's personal life, but no one can do that to him?
* LastNameBasis: 15 years and you could probably count on one hand the number of times he was called by his first name, rather than his last. It's given a LampshadeHanging in an early Season 1 episode, when he and Susan Lewis share a conversation and she admits that calling him "John" doesn't feel right, probably because Carter is [[AwesomeMcCoolName a cooler name]]. Notably, Lucy Knight is the only regular character who ever only called him John (Kerry Weaver and Jing Mei Chen refer to him as John occasionally).
* LikesOlderWomen: A good portion of his love interests were slightly (5-6 years) older than him, with Abby Keaton maxing it out at 16 years his senior. Chen--who herself was several years older than him and who he enjoyed a mild flirtation with--makes note of this and accuses him of "liking" Weaver; Carter counters that he simply doesn't ''dislike'' her the way everyone else does. He does have a flirtation with Lucy Knight (approximately 5 years his junior) but is quickly able to cut it off before it can go anywhere more than a kiss when he notes how unprofessional it would be. Ultimately [[AvertedTrope averted]] with his final main love interest, Kem, who is roughly the same age as him.
* MrFanservice
* NaiveNewcomer: He started out as this, being a 3rd-year medical student as opposed to the more experienced staff.
* NamesTheSame: [[Literature/JohnCarterOfMars John]] [[Film/JohnCarter Carter]], huh.
* NiceGuysFinishLast: It took him ''forever'' to become an attending, and only was made Chief Resident after Chen was fired. It was even implied that once his residency was over, Weaver had no intention of hiring him, and only did so because of a shortage of Attendings. And this is ''after'' being forced to repeat his first year of residency due to switching specialties and then being told he is repeating his third year thanks to his drug issues.
* NonIdleRich: Aside from going to medical school rather than joining the family business and living off their fortune, Carter transfers to Emergency Medicine just to spend more time getting to know his patients. When Kerry says they might not have space in the budget for him, he nonchalantly says he doesn't need a salary, which surprises her. Throughout the entire series, particularly in the finale, he is repeatedly shown to use the family money for charitable interests.
* TheNotLoveInterest: To Chen, despite a mutual attraction, occasional flirtation and them being one of the show's FanPreferredCouples, it never goes beyond friendship.
** Also to Maggie Doyle. They hit it off and he's clearly attracted to her. . .but she's [[IncompatibleOrientation gay]].
* PutOnABus: After season 11.
** TheBusCameBack: In season 12 for four episodes. He also came BackForTheFinale.
* SecretlyWealthy
* TallDarkAndHandsome
* TwoFirstNames
* UnresolvedSexualTension: With several people, but most obviously with Anna Del Amico.
* TheWisePrince
* YouAreInCommandNow: When Mark Greene leaves, he instructs Carter to "set the tone", just as Morgenstern had told him in the pilot episode. [[LampshadeHanging Lampshaded]] by Weaver afterwards.
-->'''Weaver''': Mark's gone. [[LeaningOnTheFourthWall That means you've been here longer than any other doctor. People will look at you to step in and fill the void.]]
-->'''Carter''': ''({{Beat}})'' Big void.
-->'''Weaver''': Yes, it is.

[[folder: Peter Benton]]
!'''Peter Benton'''
->'''Played By''': Eriq La Salle

* AngryBlackMan: To an extent. Peter is relentless in his abuse of Dennis Gant because he claims Gant, as a black man, has to work twice as hard to prove he's just as good as his white counterparts. Benton is also uncomfortable with dating Corday because she's white (largely because he's concerned about what his family might think) and resents Cleo's attempts to prove herself by being enraged at what she sees as prejudice, claiming that as a half-white woman she knows nothing about real prejudice.
* BadassBeard
* BlackAndNerdy
* DaddyDNATest: Twice. The first time Carla claims Peter may not be Reese's father. Peter goes as far as swabbing both him and Reese before telling himself and Carla that it's not important. The second time Roger challenges Peter's paternity (something Carla couldn't have done, as she put Peter's name on the birth certificate) and forces him to take a test. As it turns out, Reese's isn't Peter's biological son.
* EvenBadMenLoveTheirMamas: Is gruff and abrasive, but adores his mother. His complete denial of how ill and frail she's becoming is in stark contrast to his skills as a physician and the scene where he breaks down over her death is one of the saddest of Season 1.
* FamilyVersusCareer: Leaves County and emergency medicine for what looks like a [[HospitalParadiso rather dull clinic job]] so that he can have better work hours and get custody of his son.
* GrumpyBear
* HappilyMarried: To Cleo.
* HeroicBSOD: Peter has many. When his mother dies, when he nearly kills a baby in surgery, when Gant commits suicide, when his son is born prematurely with severe complications.
* HonorBeforeReason: Benton discovers Abby Keaton and Carter's relationship when he goes to her office to ask for a recommendation for a pediatric rotation. When she asks if he's threatening to tell TPTB about her and Carter (he's an intern and she's an attending, so it's forbidden), his response?
--> "Dr. Keaton. . .if your recommendation is based on anything but my skills as a doctor, ''I don't want it.''"
* {{Hypocrite}}: When it comes to racial issues. He claims that Cleo, as a bi-racial woman, doesn't understand the medical needs of the black community, even though he had an affair with Jeanie, who was half-white and was hired by him to take care of his mother.
** When Carter transferred to Emergency Medicine. Benton told Carter that he should have come and talked to him instead of going straight to Anspaugh, even though when Carter actually came to Benton for advice on how to deal with Dale Edson (he falsified a chart, which is illegal) months earlier Benton simply blew him off.
** He also makes his son's stepfather out to be a jerk for seeking full custody of the boy, even though he's being just as rigid and stubborn throughout the whole custody battle. Plus, the other man tries to call a truce, offering him full custody as long as he gets to visit, which Peter rejects, only for the judge to make a virtually identical decision.
* JerkWithAHeartOfGold: Despite his brusque demeanor and often questionable bedside manner, he's very compassionate and wants the best for his patients.
* MamasBabyPapasMaybe: Peter is originally presented as Reese's father, but when Carla wants to take Reese with her and Roger to Germany she suddenly claims that there was someone else. Peter eventually finds out that he isn't Reese's biological father, but he decides that he doesn't care and will be there for Reese no matter what. The fact that Reese acknowledges Peter as his father is the deciding factor in Peter's custody case against Roger.
* PapaWolf: Most prominently to his son Reese, but also to Carter, his protege. He'd do anything for his son, ultimately quitting County so that he could spend more time with him, and when Carter was stabbed another patient almost died because Benton absolutely refused to leave Carter's side.
* TokenMinorityCouple: Him and Cleo--the sole reason she was even created was to give him an African-American love interest.
* TookALevelInCheerfulness: By the time Benton finally returns to the show in Season 15, he seems far more relaxed than he generally was during his time as a cast member. His banter with Carter and Corday, in particular, is quite amicable. Spending all of those years maintaining happy relationships with both Cleo and Reese probably helped.
* UptightLovesWild: Deconstructed with him and Elizabeth. Aside from his uneasiness with their racial difference, in all likelihood the relationship would have failed anyway, as her vivacious, fun-loving personality was a stark contrast to his dour, aloof one.
* WhatTheHellHero: Abby Keaton gives this to him good and proper after he nearly kills an infant during surgery, blasting him for disregarding her instructions and not calling for help the minute he realized he was in over his head.
** Roger blasts him for trying to cut him out of Reese's life, when he's been in the boy's life almost as long as Benton has.
* WhereDaWhiteWomenAt: Averted. Despite their mutual attraction, he's very reluctant to date Elizabeth because she's white and even after they do get together, his persistent discomfort, as well as his chronic self-absorption, causes the relationship to fizzle very quickly.

[[folder: Carol Hathaway]]
!'''Carol Hathaway'''
->'''Played By''': Julianna Margulies

* AscendedExtra: She was supposed to have been killed off in the pilot--note that she's credited as a guest star, unlike the other original cast members--thanks to a suicide attempt, only to be revived thanks to positive test audience reaction. The result is that she was essentially the show's heroine for the first 6 seasons and is the cast's sole Emmy winner--she even lampshaded this in her acceptance speech, cracking that "I was dead this time last year, now look at me."
* AloofDarkHairedGirl
* BreakoutCharacter: Despite originally being envisioned as a one-off character who would die in the pilot episode, Hathaway immediately resonated with audiences and became one of the show's most popular characters. By the time of Susan Lewis' departure, she had become the female lead of the show, and her coupling with Doug Ross was easily the show's most high-profile romantic pairing. Additionally, Julianna Margulies was the only main cast member in the history of the show to win an Emmy award for her performance, and also received more nominations than any other performer (for all six years she was regularly on the show).
* ChuckCunninghamSyndrome: Doesn't appear at Mark's funeral--with zero explanation as to why--despite she and Doug being among his closest friends.
* DullSurprise[=/=]EmotionlessGirl: She spent the year after Doug's departure acting very distant and detached--there is a visible change in her demeanor as she leaves the hospital, races through the airport, and is reunited with him in Seattle.
* HeroicBSOD: Has one after accidentally killing a patient (she gave him the wrong blood). Her refusal to let the incident be covered up or used as an excuse to punish the other nurses (who were all having a sick day in protest at the time) nearly costs her her job. She has another after Doug leaves.
* HonorBeforeReason: Not only does she refuse to let her fatal error be covered up or used to punish the other nurses, she insists on taking full responsibility--even though she could have easily and legitimately blamed the others--and on being reprimanded despite knowing that it could cost her her job and possibly even her nursing license.
* LawOfInverseFertility: When she and Doug are a happy couple, they struggle to conceive. When he resigns in disgrace and leaves Chicago, they conceive twins.
* OfficialCouple: With Doug.
* OneTrueLove: Doug. It's implied, but not explicitly stated, that Carol tried to kill herself because of Doug's adulterous behaviour (she broke up with him over his many affairs, but then slept with him a month before she tried to kill herself). When he leaves for Seattle, she claims she can't remember a time that she didn't love him.
* PutOnABus
** TheBusCameBack
* RavenHairIvorySkin

[[folder: Jeanie Boulet]]
!'''Jeanie Boulet'''
->'''Played By''': Gloria Reuben

* AscendedExtra: She spent a year as a guest star before being added to the main cast
* {{Claustrophobia}}: As seen when Kerry Weaver uses her as a test subject to test the efficacy of exercise in restoring broken circadian rhythms.
* DarkSkinnedRedhead: At times.
* EarnYourHappyEnding
* HeroicBSOD: Has one after finding out she's HIV positive.
* IllGirl: She's HIV positive. Then later she contracts Hepatitis C, although she eventually gets cured.
* MoralityPet: To Kerry. For a while, she was the only person who brought out Kerry's softer side.
* PutOnABus
** TheBusCameBack
* SympatheticAdulterer: Her husband repeatedly cheats on her, making her affair with Benton a classic example of this trope.

[[folder: Kerry Weaver]]
!'''Kerry Weaver'''
->'''Played By''': Laura Innes

* AllLesbiansWantKids
* AmbitionIsEvil. And how, given the number of deceitful things she does to either advance or maintain her career, in stark contrast to Mark, who is happy to remain an attending.
* AscendedExtra: Spent a year as an extra before being advanced to the main cast. Later DemotedToExtra.
* BaitAndSwitchTyrant
* BenevolentBoss: In the earlier seasons while serving as ER chief, she could be quite nice and helpful to her subordinates who were in need. Prime examples being in dealing with Jeanie's HIV status and Carol's pregnancy. [[TookALevelInJerkass She grew out of it.]]
* BadassBureaucrat: While serving as ER chief, anyways. Its repeatedly shown that without her there to keep things on track the ER will quickly fall apart.
* BrokenBird: Despite her tough exterior there have been numerous instances where she has demonstrated herself to be really fragile underneath.
* BrokenPedestal: Frequently became this to the few people who liked and trusted her. In particular, Chen, who she mentored on her way to becoming Chief Resident before screwing her over to avoid taking any blame for a patient's death.
* ChronicBackstabbingDisorder: Her modus operandi was basically to pretend to be someone's friend/ally before screwing them over in order to save herself. This was so prevalent that one of her victims outright said "I knew she was capable of this, I just didn't think she'd do it to me.".
* ControlFreak
* CunningLinguist: Knows Spanish, Swahili, and ASL.
* DefrostingTheIceQueen: Will often do something to prove to one of the the characters that she is genuinely a kind person underneath. For example, she demonstrates to Doug that she's actually very caring when it comes to children, she keeps Jeanie's HIV status a secret and then actively campaigns to keep her on staff when it's revealed, she lets Carter live in her basement and actually somewhat takes on the role of surrogate mother to him. However, she then follows up by doing something cold or horrible to them, making sure no one ever gets close to her.
* EvilRedhead
* FieryRedhead: Whatever her numerous flaws, no one could call her a wimp or a pushover.
* FriendToAllChildren: Consistently interacted very well with kids, despite her inability to get along with anyone else.
* {{Gayngst}}: During her relationship with Kim, where she was so terrified of anyone finding out that she would barely even speak to her while at work, and at the beginning of her relationship with Sandy, where she ran and hid to avoid being seen while out on a date.
* GeniusCripple
* HeelRealization: After Mark dies and she realizes that she made his life miserable by always trying to make everything into a competition when, "the man just wanted to do his job and go home".
* {{Hypocrite}}: Countless instances of her criticizing people for doing things she had done or would do herself. She also made sure anyone who screwed up was punished as severely as possible, while acting like her own mistakes were no big deal. A few standout examples:
** Made Doug's life hell and tried to sabotage Doug's career advancement because he was such a cowboy, and yet almost as soon as he leaves she tries to circumvent a standing DNR order (because she thought the woman was her biological mother)--then months later hounds Mark for doing the same thing, having the gall to insinuate that Mark isn't being objective because of the recent death of ''his'' mother, even though in this case, the patient had explicitly rescinded her DNR, telling Mark that she didn't want to die just yet.
** Pulls out all the stops to make sure Chen and Malucci are severely punished for their part in a patient's death--firing the latter and suspending the former, yet is just as vigilant in making sure that she herself incurs no punishment, even though as their supervisor, she bore the ultimate responsibility.
** Pleads with her ex-lover Kim to fight Romano's efforts at firing her (because she's a lesbian)--while she herself continues to keep her mouth shut.
** Hemmed and hawed about reporting her Alzheimer's stricken mentor, but instantly reported Mark for his impairment.
* HypocriteHasAPoint: After a patient dies because he slept with a paramedic on duty, Dave is fired by Kerry for irresponsibility. Although Kerry, as Dave's supervisor, should have kept a closer eye on him, Dave's behavior is indeed completely unbefitting of that of a doctor.
* InferioritySuperiorityComplex: Big time. Her obsessive need to excel clearly stems from feelings of inadequacy regarding her disability and that she was put up for adoption.
* InspectorJavert: There were times when she was downright fanatical in her insistence that people adhere to rules and policy, not believing in making the slightest of allowances for any reason.
* ItsAllAboutMe: Had a bad habit of this whenever things got tough. When her girlfriend is investigated for sexually harassing/assaulting a patient, the woman comes to her, clearly looking for some compassion and support. Kerry's only reaction is to ask if she's told anyone about their relationship, which she wants to keep secret, fearing that their homophobic supervisor will find some contrived reason to fire her. Kerry promptly spends the rest of the episode doing everything she can think of to make sure that the relationship remains a secret, to the point where she refuses to even ''look'' at the woman, much less say a single word in her defense, lest it make anyone suspect that they're involved. When the hurt, angry, and fed-up woman dumps her, Kerry ''still'' doesn't get it, accusing her of not considering Kerry's feelings in the whole mess.
* JerkassHasAPoint: One of her defining traits, especially when it comes to the ER budget. She might be an ass, but it's not her fault that the hospital doesn't have the money for more vital equipment.
--> "Mark, just because something's my idea doesn't make it a ''bad'' idea."
** She's also rightfully pissed off at her girlfriend Sandy when the woman outs her in front of ER staff by planting a ForcefulKiss on her. It's not Sandy's place to decide that Kerry should be out of the closet.
* KarmaHoudiniWarranty: Kerry's double-dealing almost always puts her at the head of the pack, until toward the end of the show she finally made the mistake that cost her her career: her newest hire Dr. Clemente, though a genuinely talented doctor, was also an extremely violent paranoid schizophrenic. She's out the door a few episodes later. [[AlasPoorVillain It's still really sad]].
* LipstickLesbian: Of the "chapstick" variety. Short-haired and abrasive, but very pretty and when she's not at work, she's rather feminine.
* MysteriousPast: It took ''ten'' years to find out why she needed a crutch to walk.
* NeverMyFault: Rarely, if ever, saw her responsibility for whatever problems she had with other staff members and dumped the blame for a patient's death squarely onto the two doctors who treated him, conveniently ignoring the fact that as their supervisor, she should have been present to correct their mistakes, rather than off-site handling personal business.
* NiceGuysFinishLast: She proves this repeatedly as she angles her way into positions of authority while engaging in ChronicBackstabbingDisorder, BaitAndSwitchTyrant and NeverMyFault. She started out as Chief Resident in the ER, eventually started running the ER, even though Mark Greene had more seniority and had more respect (and was a better doctor), eventually becoming Chief of Staff of the entire hospital.
* ThePeterPrinciple: With each promotion, Weaver proved herself unworthy of them, at least to the audience. Thanks to her NeverMyFault tendencies, and the fact that she was such a RulesLawyer when it came to subordinates that she was more than willing to find and highlight their mistakes over her own, she was rarely ever called out for this, and just kept moving up. Finally it came back to bite her, and she lost her job.
* PetTheDog: Could be genuinely compassionate with her patients when necessary.
* PutOnABus
** TheBusCameBack
* RealLifeWritesThePlot: Her having surgery to fix her limp was done because Laura Innes was starting to develop real hip problems after faking it for so long.
* [[SecondEpisodeIntroduction Second Season Introduction]]: She's one of the show's longest running characters--11 years--but didn't join the show until its second year, and didn't even become a main character until the third.
* StrawmanHasAPoint: Her insistence that staff abide by rules and policy. Unfortunately, this was undermined by her aforementioned hypocrisy as well as the way she basically tried to bully people into submission.
* SuddenlySexuality: Prior to her relationship with Kim Legaspi, Kerry had several relationships with men, even revealing to Kim that she had been married once before.
* SugarAndIcePersonality
* SweepsWeekLesbianKiss: Twice. Unlike most examples, however, this wasn't just a ratings grab, but rather part of a larger arc involving Kerry coming to terms with her sexuality. Both of the women she kissed appeared again.
* TinyTyrannicalGirl
* TooHappyToLive: Is blissfully happy with her girlfriend and her newborn son just before the woman is killed in a fire.
* UptightLovesWild: Her and her girlfriends upon her coming out of the closest. Aside from their carefree, fun-loving personalities clashing with her prim and proper one, they were also comfortable and open with their sexuality while Kerry acted downright terrified to even be seen with them in public, at one point literally hiding to avoid running into two of her coworkers while out on a date.

[[folder: Anna Del Amico]]
!'''Anna Del Amico'''
->'''Played By''': Maria Bello

* InferioritySuperiorityComplex: Had an incredibly sanctimonious attitude towards rich people, probably stemming from insecurities about growing up poor.
* MsFanservice
* PutOnABus
* RedHerring: As a pediatrician, there was speculation that she'd been brought on to be a new girlfriend for Doug--indeed, she initially seems very attracted to him. Only for Doug to reconcile with Carol as had been hinted at for weeks and Anna to be a love interest for Carter instead.
* StrawFeminist: She tended to react to everything Doug said as though it was an attack or an advance, even though he was either just being friendly (asking her if she wanted something to eat after they'd both been on the streets looking for a runaway) or just offering his years of experience (offering to do a testicular exam on a patient because he might be uncomfortable with a woman doctor). Kerry Weaver seems to agree with her claim that Doug is threatened by women, but of course Kerry had been brow-beating and annoying him about publishing his thesis for his fellowship and just couldn't see that Doug (or anyone else for that matter) simply didn't want her help.
** Nor it did occur to Kerry that Doug's problem was simply with ''her'', given her abrasive personality and their constant clashes and nothing to do with her gender.
* TheyCallMeMisterTibbs: Basically rips Doug's head off when he calls her by her first name rather than "Dr. [=DelAmico=]" in front of a patient. Keeps doing it even though he apologizes and assures her that he meant nothing improper, "I call Mark (a male doctor) by his first name all the time.".
* UnresolvedSexualTension: With Carter.
* WeHardlyKnewYe: Lasted only a season.

[[folder: Elizabeth Corday]]
!'''Elizabeth Corday'''
->'''Played By''': Creator/AlexKingston

* TheBusCameBack
* ClingyJealousGirl: When Susan returns. Granted, Elizabeth has a point, as Mark loved Susan passionately enough to race to Union Station to tell her so, and then had a small breakdown when she left.
* FieryRedhead
* GoodBadGirl: Very openly sexual in her conversation and behavior, especially when first introduced.
* HerHeartWillGoOn
* HeroicBSOD: Elizabeth treated a patient from Zambia who suffered from back pain, caused by a herniated disc. The patient didn't want open back surgery and Elizabeth had planned to go on a trip with Mark that evening so she suggested a less invasive procedure instead. The patient ended up paralyzed after leaking cerebral-spinal fluid and he sues Elizabeth for malpractice. The case eventually gets settled because the patient decided to sue the manufacturer of the surgical equipment instead, but Elizabeth continued to blame herself for the incident (even though the reason he was paralyzed in the first place is because one of the waldoes wouldn't grip the bone fragment in his spine) and promptly spent weeks avoiding the OR at all costs
** Elizabeth has a break down during her wedding, making known her fear that Mark's tumour will return and her fear of him being hurt or ending up dead. Fears that end up being realised.
* {{Hypocrite}}: Is pissy about Mark and Susan working together, even though they were never really romantically involved, even though every day she works side-by-side with her ex-lover.
** She also chastises a fellow surgeon who asks her to speed up an operation because he wants to go to a ball game, when she herself rushed through an operation because she wanted to leave for a romantic weekend with Mark, permanently crippling the patient (to be fair, it could be that it's because of this error that she's lecturing the other doctor).
* ItRunsInTheFamily: Her mother and father are both scientists. Her father is a surgeon, her mother is a physicist.
* OneTrueLove: Mark, despite the character being introduced as a LoveInterest for Peter Benton. Elizabeth's relationships before and after Mark all fail for one reason or another, in the latter case probably because of [[TheLostLenore her love for Mark]]. When Peter asks her if she's seeing anybody in the series finale (seven years after Mark's death), she says that she's become far more focused on raising her daughter and working on her career.
* PutOnABus
* ReplacementLoveInterest: For Susan, with Mark Greene.
* SomeoneToRememberHimBy: Mark did manage to give her a daughter, and spend the first year of her life with her (long enough to hear her say her first words and see her learn to walk) , before he finally succumbed to cancer.
* TheyCallMeMisterTibbs: Inverted. She's confused when someone refers to Peter, a surgeon, as "Dr. Benton" and needs to adjust to being called "Dr. Corday", rather than "Miss", as she was back in England.

[[folder: Lucy Knight]]
!'''Lucy Knight'''
->'''Played By''': Kellie Martin

* AudienceSurrogate: Brought in because Carter, the previous audience surrogate, was now a fairly experienced and accomplished doctor.
* CharacterDevelopment: Despite her brief time on the show, she went from being a bumbling, clueless medical student to a very competent one who would no doubt have been an excellent physician.
* CousinOliver: It was explicitly stated that she was brought on to bring some new blood to the now five-year old series.
* TheCutie
* DistaffCounterpart: As an inexperienced 3rd-year medical student, she was essentially a female version of 1st-season Carter.
* KillTheCutie
* MoralityPet: For Romano.
* NaiveNewcomer
* WeHardlyKnewYe: Lasts only a season and a half. Despite the professional development that Lucy undergoes, the audience never gets to know much about her personally.

[[folder: Robert Romano]]
!'''Robert Romano'''
->'''Played By''': Paul [=McCrane=]

* AlliterativeName: Combined with his nickname 'Rocket', he has a triple alliterative name.
* AnArmAndALeg
* AscendedExtra: Made frequent appearances during Seasons 4 and 5 before being bumped up to series regular status in Season 6.
* AtLeastIAdmitIt: For all his numerous flaws, as Cleo called him, "a racist, sexist, elitist jackass", there was no denying that he never once hid the fact that he was a colossal egomaniac who couldn't be trusted and whose primary concern was himself.
* BaldOfEvil
* DeadpanSnarker
* DrJerk
* DroppedABridgeOnHim
* EvenBadMenLoveTheirMamas: A episode that took place near Mother's Day had him enthusiastically describing the elaborate plans that he had for his mother, much to the shock of the other staff members.
--> '''Romano''': Bet you didn't even think I ''had'' a mother, did you?
--> '''Haleh''': Can't imagine what she's like.
* EvenEvilHasStandards: Is genuinely angry and disgusted at the dishonest stunts Kerry pulls.
* {{Flanderization}}: When he first appeared his bad traits were relatively low-key. The more often he appeared, the worse he got.
* HeroicBSOD: After his arm is reattached and he realizes he might never regain full mobility, then after he realizes it can't be saved and needs to be amputated for good, effectively ending his surgical career.
* HiddenDepths: Adores his dogs, studies martial arts (as evidenced by him showing up at work in such a uniform), is a member of the Polar Bear Club (he mentions it to Susan in one season 8 episode and a deleted scene [[FanDisservice shows him in a Speedo]] having taken one of the elderly members to the ER) and knows sign language.
** He is also the only one to tell Corday to go back to Mark. This is especially a touching scene because Corday was probably the only woman he had genuine above-the-belt feelings for, and yet he told her to go back to her husband instead of attempting to use her moment of weakness to his advantage.
** His devastation at the realization that he might never be able to perform surgery again--a fear that ultimately comes true--reveals that for all his {{Jerkass}} ways, he genuinely loves his job and being able to help people.
* InsufferableGenius
* JerkassHasAPoint
* KindheartedCatLover: Rushes his own dog into surgery because he refused to trust her welfare to "some poodle surgeon."
* LonelyFuneral: Romano was so disliked that Corday was the only one to show up.
* PetTheDog: However rare they were, his NiceGuy moments were genuine. Even some of his supposedly {{Jerkass}} moments revealed that he was actually doing someone a favor--assisting a heavily pregnant Elizabeth with surgery, giving Peter time off to spend with his son, concern for the ailing Mark. Plus, the literal examples with his beloved animals, as well as his genuine fondness for Lucy Knight.
* PoliticallyIncorrectVillain
* ShoutOut: When he's in the OR he wears a bandana with rockets on it. Whether the bandana or the nickname came first is never specified.
* TokenEvilTeammate
* {{Ubermensch}}
* UglyGuyHotWife: Romano has been seen with some very attractive girlfriends.

[[folder: Luka Kovač]]
!'''Luka Kovač'''
->'''Played By''': Creator/GoranVisnjic

* BerserkButton: Wife-beaters, child-abusers, just AssholeVictim patients in general.
* TheCasanova: Like Mark, Luka had never been with anyone other than his wife before he started seeing other women. Unlike Mark he actually knows how to charm them.
* ChronicHeroSyndrome: Likely because he was unable to save his own family during the war, he develops this, often to his detriment--he takes a waitress from his favorite bar under his wing, blithely ignoring all signs that she's a thief and a liar.
* CommutingOnABus: Throughout Season 14. Notably, Goran Višnjić does not appear on the DVD cover for the season, but is first-billed as a member of the main cast in all of the episodes he appears in (7 out of 19). In-universe, Luka spends most of it off-screen in Croatia to be with his dying father, occasionally appearing to see Abby and their son Joe. He eventually returns to Chicago full-time, only to spend time away from Abby when she reveals that she cheated on him. He forgives her in the season finale, and turns up one final time in the second episode of Season 15 for them to depart County Hospital together.
* DarkAndTroubledPast
* EarnYourHappyEnding: After everything Luka went through both before and after the series, he eventually got a happy ending with Abby and their son.
* HeroicBSOD: Plenty of these for him too, all of which seem to happen just as things are getting better for him--he starts to recover from the loss of his wife and children by falling in love with Carol--then she leaves him. He starts to recover from ''this'' by dating Abby, then kills a mugger attacking them. One even happens out of nowhere then gets even worse after he almost kills a co-worker in a car accident.
* IWantYouToMeetAnOldFriendOfMine: Goran Višnjić actually worked with George Clooney on The Peacemaker a few years before he joined the ER cast as his replacement.
* ShellShockedVeteran
* SuspiciouslySimilarSubstitute: A brooding hunk with allusions to a mysterious, tragic past and a not-so-secret longing for Carol? He was referred to as "Euro Ross" on many other fan boards (his resemblance to Doug didn't help much to dispel this). A period of promiscuity for him pretty much cinched it. Not to mention the fact that he fell in love with and eventually married Carol's effective replacement.
* TallDarkAndHandsome
* TroubledButCute
* UnresolvedSexualTension: With Carol. Especially bad as from his side of things, developing feelings for her was an indication that he was recovering from the deaths of his wife and children.
* YoungerThanTheyLook: Actor Goran Višnjić was 27 during his first year on the show. He easily could have passed for 40 and was immediately shown to be an authority figure (already an Attending) in the ER. Which also makes this a case of either PlayingGertrude or ImprobableAge, as there's no way he'd be an attending so young.

[[folder: Cleo Finch]]
!'''Cleo Finch'''
->'''Played By''': Michael Michele

* ClingyJealousGirl: Gets pissy about going to Mark and Elizabeth's wedding, even Benton and Elizabeth broke up ''three years before''.
* DarkSkinnedBlond
* DistaffCounterpart: To Benton. Her aloof, reserved personality is very similar to his.
* HalfBreedDiscrimination: Against ''herself''. It's implied that the reason for her hypersensitivity about race issues is compensation for being of mixed race and having grown up in the suburbs.
* HappilyMarried: Apparently, to Benton as of the finale.
* {{Hypocrite}}: Her few scenes with Elizabeth indicate that she disapproves of the fact that she and Peter once had a relationship, even though she herself is the product of such a union.
* MalcolmXerox: For a while, tended to see racism as the reason behind every slight or reprimand.
* PluckyGirl
* PutOnABus
** TheBusCameBack
* SuspiciouslySimilarSubstitute: Inverted. She's Doug's opposite in practically every way, right down to their race and gender, except for being a skilled and dedicated pediatrician just like he was.

[[folder: Dave Malucci]]
!'''Dave Malucci'''
->'''Played By''': Erik Palladino

* AscendedExtra: Spent his first few episodes credited as a guest star before being added to the opening credits.
* AbusiveParents: Implied, given his reaction to them.
* CasanovaWannabe: Hits on practically every woman in sight, all of whom reject him. Even the woman he's caught having sex in an ambulance with blew him off initially.
* CunningLinguist: Speaks Spanish.
* DumbassHasAPoint: On several occasions.
* DumbJock: A doctor variant. Attended medical school in Grenada because he did poorly in college and on his [=MCATs=].
* HiddenDepths: Claims to have a child, although this may have been an appeal to Weaver's emotions.
** He actually proved to be a pretty decent doctor on the rare occasions that he got his act together and stopped goofing off.
* IdiotBall: Despite knowing full well that Weaver is out for blood due to his part in killing a patient, Malucci sneaks off to have sex with a gorgeous paramedic. Weaver catches him and subsequently fires him.
* JerkWithAHeartOfJerk: Unlike Doug there's very little beneath that philandering DumbJock exterior. He's ultimately fired for having sex in an ambulance, with his one moment of depth (see above) being in his very last episode.
* KickTheDog: Malucci claims to have a child to support. Kerry fires him anyway. Later, Malucci's last mention on the series was Carter telling Gallant that he was reckless and killed a patient.
* NosyNeighbor: Shortly after joining the staff, he interrogates everyone about why Kerry limps. He finally admits it's none of his business after she confronts him about it, but still fails to learn his lesson--one year later, he does exactly the same thing regarding the paternity of Chen's baby.
* PetTheDog: Despite his incompetence and the rest of the staff's utter contempt for him, Mark Greene seems to rather like Malucci and stands up for him when Kerry Weaver fires him. Perhaps it's because he reminds him of Doug.
* SuspiciouslySimilarSubstitute: Like Luka, was given many of Doug's characteristics--brashness, impulsiveness, problems with authority, an antagonistic relationship with Weaver (bizarrely, in ''both'' cases, fanfic writers opted to interpret this as BelligerentSexualTension and pair them), and a once-mentioned but never explained kid, along with a BerserkButton reaction to abusive parents that likely stemmed from his own experiences. To the point where ''his'' fan board nickname was "Doug Ross, Jr."
* WeHardlyKnewYe: Lasted only a little over two seasons and got zero CharacterDevelopment.

[[folder: Jing-Mei Chen]]
!'''Jing-Mei Chen'''
->'''Played By''': [[Creator/MingNaWen Ming-Na Wen]]

* AsianAndNerdy
* AscendedExtra: She was a recurring character in season 1. 5 years later, she would become a regular.
* ChekhovsGunman
* ClingyJealousGirl: Is understandably pissy about Pratt flirting with Neela right in front of her, but she unfairly takes it out on ''Neela'', who was completely unaware of their relationship.
* GoodGirlsAvoidAbortion: When she reveals her pregnancy to Weaver, she implies that she deliberately hemmed and hawed about what to do until it was too late to terminate.
* FamilyVersusCareer: Having quit her job in anger after realizing that Weaver screwed her over, she tearfully tells Carter, "Whatever sacrifice you make for this place, make sure it's worth it" , indicating that the reason she gave up her son for adoption was to focus on her career and that she now regrets it.
** She also quits for good to euthanize her dying father and bury him in his native China.
* HeroicBSOD: Has at least two. One after the infamous guide wire incident. Another for simultaneously giving up her son for adoption (she knew she could've easily taken care of him but was too concerned with what her overly traditional family might think) and for losing a patient and being back-stabbed by Kerry Weaver.
* ItRunsInTheFamily: Her parents are doctors as well.
* NeverLiveItDown: The guide wire incident. Chen left a guide wire in a man's chest when she was a med student. Six years later Carter brings the incident up as a a way [[InsaneTrollLogic of proving that he's not a drug addict and that he's not spiraling out of control]] and Weaver and Romano use the incident as pretence to demote her from her position as Chief Resident following her and Malucci's accidental killing of a patient.
* TheNotLoveInterest: To Carter. Despite a slight attraction and flirtation, their relationship never goes beyond a very good friendship.
* TheOjou
* OnlyKnownByTheirNickname: When she first appeared she went by her western name, Debra 'Deb' Chen. When she returned as Jing-Mei, Carter insisted on always calling her 'Deb'.
* PutOnABus: After season 1.
** TheBusCameBack: Returned as a regular from halfway through season 6.
** Then she's PutOnABus again in Christmas of 2004, leaving Chicago to bury her father in his native China.
* ScrewThisImOuttaHere: Chen actually resigns altogether following her demotion and Kerry Weaver's backstabbing.
** There's a sadder version several years later when she can no longer keep up with the demands of her job and caring for her ill father, especially when Susan tells her that she can no longer make allowances for her.

[[folder: Abby Lockhart]]
!'''Abby Lockhart'''
->'''Played By''': Maura Tierney

* AbusiveParents: Subverted. While her mother may not have been willfully abusive or neglectful, it's still clear that Abby's childhood was hell thanks to her mother's UsefulNotes/BipolarDisorder, a mental illness that she consciously chose not to seek help for.
--> '''Maggie''': I never asked to be sick!
--> '''Abby''': You never tried to get better!
* TheAlcoholic
* AscendedExtra: In her first appearance, she was an OB nurse at Carol's birth. Not long after, she appeared in the ER as a medical student, and was later transferred to be an ER nurse after being forced to drop out of medical school.
* DeadpanSnarker: Has her moments. Most notably as a nurse and occasionally after she has Joe.
* EarnYourHappyEnding: After everything, Abby finally gets her happy ending with Luka.
* GoodGirlsAvoidAbortion: Averted. She had one during her first marriage out of fear of putting a child through the same hell she went through, or the child itself being mentally ill. But played straight when she gets pregnant by Luka, despite still having the same fears.
* JadeColoredGlasses
* TheMasochismTango: She outright calls her and her mother's interactions "The dance we do"--she shows up in the beginning stages of mania, swearing that things are going to be different, but eventually going completely off the wall and causing chaos, then disappearing for months before turning up again, this time in a depressed phase, possibly to the point of being suicidal. Despite how miserable the whole thing makes Abby, it's obvious that she can't bring herself to get out of it.
* OffTheWagon
* ParentalSubstitute: Was this to her own mother and brother whenever her mother was in a manic or depressive state.
* PutOnABus: Near the very beginning of the final season ("The Book of Abby"), she leaves the ER to be with Luka. She makes one final return in "Shifting Equilibrium" via [[TheCameo phone call]] in order to reassure Neela on the latter's last day working at County Hospital.
* ReallyGetsAround: It's implied that she slipped into this kind of behavior whenever she was drinking.
* SingleWomanSeeksGoodMan
* SuspiciouslySimilarSubstitute: After Lucy Knight was killed, replaced her as the "bumbling & clueless" medical student. Then, though their personalities and backgrounds were vastly different, she replaced Carol Hathaway as the token nurse character once the latter left. Interestingly, when she first appeared on the show, she was precisely at the point Carol would have been in her medical studies had she decided to go to medical school.
* YourCheatingHeart: Her first husband cheated on her (in his defense, this was after she froze him out following her abortion), and she sleeps with another man while Luka is away in one of her alcohol-induced blackouts.

[[folder: Michael Gallant]]
!'''Michael Gallant'''
->'''Played By''': Sharif Atkins

* CommutingOnABus: In seasons 11 and 12 [[spoiler:until he died.]]
* FourthDateMarriage: He expressed interest in Neela but was shipped off to Iraq before ever getting to officially ask her out. From then on, their courtship takes place via letters and e-mails. It's not known if they ever even HAD a proper date before he returns on leave and proposes to her, with them marrying very soon afterwards before he's sent back. This is acknowledged when shortly after they've married and Gallant is preparing to return to Iraq, much to Neela's dismay, she admits, "I love you, but I don't *know* you".
* GoodLookingPrivates: Whenever we'd see him in uniform.
* KilledMidSentence
* MeaningfulName: Gallant, obviously. To the point where his final episode is named after him--"The Gallant Hero & The Tragic Victor"
* PutOnABus: After season 10.
* RedOniBlueOni: With Pratt. Pratt is more impulsive, Gallant is by the book.
* TooHappyToLive: [[spoiler: Mentions his wife and how much he's looking forward to going home and seeing her not five seconds before the truck he's riding in is blown up, killing him]]
* TookALevelInBadass
* WideEyedIdealist

[[folder: Gregory Pratt]]
!'''Gregory Pratt'''
->'''Played By''': Mekhi Phifer

* BackForTheDead
* BadassBeard
* BlackBestFriend: Inverted. While he is technically this to Morris, he is the more prominent character.
* CharacterDevelopment: Started out very impulsive and egotistical. By his tenure's end, he'd become an excellent teacher and was about to be named ER Chief.
* MeaningfulName: He ''is'' a bit of a prat, after all.
* RedOniBlueOni: With Gallant.
* SuddenSequelDeathSyndrome: [[spoiler:Died at the ''final season'' premiere.]]
* TooHappyToLive: [[spoiler: Was preparing to propose to his girlfriend and had just been named the new ER chief when he was killed.]]

[[folder: Neela Rasgotra]]
!'''Neela Rasgotra'''
->'''Played By''': Parminder Nagra

* AsianAndNerdy: Is Indian and a medical student/doctor/surgeon.
* BewareTheQuietOnes
* CharacterDevelopment: Goes from a shy neophyte, to confident physician to even more confident surgeon.
* {{Claustrophobia}}
* CommutingOnABus: Officially departs the ER in the antepenultimate episode, but manages to make brief appearances in the final two episodes.
* HerHeartWillGoOn
* NaiveNewcomer
* ProgressivelyPrettier: Goes from merely "cute" when she first joins the staff to positively drop-dead gorgeous by the time she leaves.
* SheCleansUpNicely

[[folder: Samantha Taggart]]
!'''Samantha Taggart'''
->'''Played By''': Creator/LindaCardellini

* AllGirlsWantBadBoys
* Badass: See EstablishingCharacterMoment.
* ClingyJealousGirl: Is furious when she sees that Luka has hooked up with the woman he had a fling with while in Africa, even though she herself told him she wanted to take a break. She later gets pissy when Neela develops a crush on him. A few years later, while dating Gates, she does the same thing--breaks up with him outright, but gets angry when he begins dating someone else.
* EstablishingCharacterMoment: Proceeds to take a needle of a sedative from Archie, jumps in and proceeds to inject the sedative into a mentally disturbed guy who was being incredibly aggressive.
* GoodGirlsAvoidAbortion: By the time she saved the money for an abortion, she couldn't work up the nerve to go through with it.
* MamaBear: And how.
* SuspiciouslySimilarSubstitute: Replaced Abby as the token nurse once Abby decided to return to medical school, though their personalities were very different.
* TeenPregnancy: She had her son at 15. Unlike most teen pregnancies though, Sam and her son are fairly level-headed.
* WifeBasherBasher: Punches out an abusive boyfriend when he not only calls the girl a slut, he grabs Sam's arm, arguably making her actions self-defense.

[[folder: Ray Barnett]]
!'''Ray Barnett'''
->'''Played By''': Shane West

* ButtMonkey
* HopelessSuitor: With Neela, at first.
* InspirationallyDisadvantaged: Following the accident that results in the amputation of both of his legs. When he returns to Chicago for a visit, he's been fitted with prosthetics and is living as normal a life as possible and has used his injuries to focus his medical practice on those in similar situations.
* MrFanservice: Essentially getting introduced as part-time doctor and part-time rock musician meant that this was nearly inevitable.
* PutOnABus: Following his accident at the end of Season 13.
** BackForTheFinale: After being absent for all of Season 14, he reappears throughout the final season (far more well-adjusted than he had been in the past), and reignites his relationship with Neela. She ends up leaving County Hospital to be with him in the antepenultimate episode.

[[folder: Archie Morris]]
!'''Archie Morris'''
->'''Played By''': Creator/ScottGrimes

* {{Adorkable}}
* ButtMonkey
* CharacterDevelopment: Probably the most extensive in the show's history. Started out as an annoying, bumbling, incompetent fool who no one liked. Ended as one of the best doctors in the hospital whom everyone respected.
-->'''Carter''': Looks like you followed my advice, Archie.
-->'''Archie''': How's that?
-->'''Carter''': [[ArcWords You]] [[CrowningMomentOfHeartwarming set]] [[PassingTheTorch the tone]].
* TheConfidant: Abby [[LampshadeHanging lampshades]] that, by the end of the series, he's become a trustworthy person to come to when it for sharing one's issues. This is reinforced later when Catherine Banfield reveals her history with County General to him (she had brought her son there for treatment and he had died there) and Simon Brenner confides to Archie about getting molested as a child.
* DrugsAreBad: He got better.
* PluckyComicRelief: In the first few years of his tenure. Downplayed later on, though he still gets his comedic lines.
* TheStoner: He got better.

[[folder: Tony Gates]]
!'''Tony Gates'''
->'''Played By''': Creator/JohnStamos
* PromotionToOpeningTitles: He debuted as a paramedic prior to joining the actual cast.
* MrFanservice
* TallDarkAndHandsome

[[folder: Simon Brenner]]
!'''Simon Brenner'''
->'''Played By''': Creator/DavidLyons

* BelligerentSexualTension: After weeks of being at each others throats, he and Neela get into a full-fledged shouting match, which of course culminates in them going at it.
* DidNotGetTheGirl: Despite falling in love with Neela, she leaves him to be with Ray.
* EvilBrit: More like "{{Jerkass}} Aussie", but the gist is the same.
* FieryRedhead
* LadykillerInLove: His womanizing ways are established from his first scene, but he falls in love with Neela.
* RapeAsBackstory: His BerserkButton reaction to a pedophile patient leads to him confessing to Morris that he was molested by one of his mother's boyfriends.
* ReallyGetsAround: His ''first'' scene is of him waking up in bed [[AThreesomeIsHot with two women]], and his womanizing reputation is well established afterwards.
* SuspiciouslySimilarSubstitute: He has a few of Doug's characteristics, namely an abusive past that influences his good (anger about abused children) and bad (sleeping around) behavior.

[[folder: Catherine Banfield]]
!'''Catherine Banfield'''
->'''Played By''': Creator/AngelaBassett

* BlackBossLady
* BrokenBird
* ChekhovsGunman: [[spoiler:Her son was one of Dr. Greene's last few patients.]]
* DefrostingIceQueen
* RememberTheNewGuy: Despite [[spoiler: her son supposedly being one of Dr. Greene's last patients, she was nowhere to be seen in season 8]].
* SecondEpisodeIntroduction: She makes her first appearance in the second episode of the final season, following Greg Pratt's death in the first episode.
* SuspiciouslySimilarSubstitute: Bossy, abrasive, takes charge and takes no nonsense? Sounds a lot like either Kerry Weaver or Angela Hicks.

[[folder: Jerry Markovic]]
!'''Jerry Markovic'''
->'''Played By''': Abraham Benrubi

* HeterosexualLifePartners[=/=]VitriolicBestBuds: Eventually became this with Frank (although they'd never admit it)
* PluckyComicRelief
* WhyDidItHaveToBeSnakes?: Had a fear of dead people early on in the series. Also afraid of thunderstorms, although the latter seems to be justified.
* CommutingOnABus: Appeared regularly up until Season 4, disappeared for a bit in the middle of Season 4 (was moved to nights due to accidentally blowing up the ambulance bay), then left at the end of Season 5 for unknown reasons. Returned again during Season 8, left again during Season 13 and returned partway through Season 15. The Season 13-15 absence was LampShaded in show as Jerry "slinging beers in Alaska" which was a reference to Benrubi's character on Men In Trees.
* GentleGiant: Was used as a bouncer of sorts on occasion, but never really got violent with anyone.
* NewPowersAsThePlotDemands: Became a Minister when Neela and Gallant were due to get married and became the ER's ASL interpreter partway through Season 12. None of these had been brought up prior to when they were needed and in the case of the ASL, he had never been shown signing to anyone on staff, let alone teaching Benton. It is possible that he learned after Peter's departure, but it's never really made clear.

[[folder: Frank Martin]]
!'''Frank Martin'''
->'''Played By''': Troy Evans

* AscendedExtra: Debuted all the way back in Season 1 as a cop.
* BigEater: Oh boy. This led to his heart attack.
* DeadpanSnarker: A LOT. Sometimes this was combined with his {{Jerkass}} behaviour, other times it was his method of communicating.
* HiddenDepths: Was later revealed that he had a wife and a daughter with what looked like Downs Syndrome and was also a war veteran.
** His reaction to the deaths or injuries of various staff members (Mark, Gallant, Jerry, Pratt) reveals that he genuinely likes and respects them despite his gruff demeanor.
** He's also a very good cook, as indicated when he gives Dr. Banfield a recipe when she's debating what to prepare for her visiting in-laws.
** Goes all out to give Neela a nice going away party as a means of apologizing to her for the bigoted comments he made about her ethnicity and nationality when she first joined the staff.
* TheGenerationGap: Was implied to be the reason behind his jerkass behaviour. The further along the series went, he became less of a {{Jerkass}}.
* FriendToAllChildren: Does make some snarky remarks about the staff's kids behind their back, but is shown to be more patient and concerned for their health and wellbeing compared to other patients.
* {{Jerkass}}: To begin with. He got better after the heart attack though, eventually advancing to JerkWithAHeartOfGold.
* SuspiciouslySimilarSubstitute: To Jerry at the time.