* ''Franchise/StarTrek''
** The pilot of ''Series/StarTrekTheNextGeneration'' features an unnamed, curly-haired conn officer played by Colm Meaney. That character would reappear on a regular basis in subsequent episodes as a gold-shirted (the 24th-century equivalent of RedShirt) transporter operator. That operator eventually got a name and rank, Chief Miles O'Brien, and ended up becoming a semi-regular character with a wife and family who interacted regularly with the main cast. When it came time to create a {{spinoff}} of TNG, O'Brien went even further to become a main character in ''Series/StarTrekDeepSpaceNine''. Miles O'Brien is the embodiment of a character working up from the RedShirtArmy to donning fullblown PlotArmor.
** ''Series/StarTrekDeepSpaceNine'':
*** Damar ascends from the role of one of Dukat's nameless henchmen to that of national hero for Cardassia in the final episode. The main difference between O'Brien and Damar is that (at least according to WordOfGod) Damar was always intended to play a major role in the Dominion War, while O'Brien was only a nameless extra in the TNG pilot (Meaney got the part as a sort of consolation prize; he was runner-up in another role).
*** Garak was only intended to appear as a guest star in a pair of episodes, but Andrew Robinson's performance impressed the producers so much that he was brought back for more and more episodes, to the point that he has a pivotal role in the final string of season 7 episodes.
** Many bit characters from the ''Franchise/StarTrek'' shows have become major players in the tie-in novels, even starring in some of the book-only spinoff series. ''StarTrekNewFrontier'' made regulars out of one- or two-shot ''Next Generation'' characters Shelby, Selar, and Lefler. ''StarfleetCorpsOfEngineers'' features guest engineers like Sonya Gomez, Duffy, and Stevens. A major character in the ''StarTrekDeepSpaceNineRelaunch'' novels (Vedek Yevir) is based on an extra who appeared in one scene and was only seen from behind. ''StarTrekExMachina'', a sequel to ''Film/StarTrekTheMotionPicture'', bases most of its supporting crew characters on faces (and alien masks) in the crowd from a crew-assembly scene in that film. Meanwhile, Agents Lucsly and Dulmur of the Department of Temporal Investigations, who were minor joke characters with less than four minutes of screen time in one episode of ''Deep Space Nine'', have been the focus of several works of short fiction, culminating in [[StarTrekDepartmentOfTemporalInvestigations an entire novel about the DTI]].
** An averted example is ''Series/StarTrekVoyager'''s Tom Paris, who was originally supposed to be the same character as Nick Locarno, a one-off character from ''Next Generation.'' Because the producers would have to pay royalties to the episode writer, the character was given a new name, but kept the same actor, personality, and backstory. (The writers say it's because Locarno was irredeemable, but that rings pretty hollow when the ''only'' change to the backstory is that where ''one'' person died in the Locarno version of the incident, ''three'' died in the otherwise-identical Paris version.) Tom's father's picture of Tom as a cadet is even a still of Locarno taken from that episode.
*** The ''Trek'' producers are notorious for that. Locarno-into-Paris is the big one, but other instances of same-actor, same-personality, new-name {{Expy}} characters who are [[SuspiciouslySpecificDenial absolutely, positively new characters who are definitely not just renamed versions of one-shots they don't want to pay royalties for, no-siree]] include Taurik[=/=]Vorik and Gul Macet[=/=]Gul Dukat. Though not with the same actor because she had to get [[{{Prequel}} younger]], not older, ''Enterprise's'' T'Pol was originally planned to be T'Pau (whom we would eventually see in a three-parter.) Also, Michelle Forbes was intended to reprise Ro Laren but declined, ''twice.'' [=DS9=]'s Kira and Voyager's Torres were both originally planned as her. Not that Ro was just an ''extra.''
** Painfully averted in ''Series/StarTrekVoyager'' by Lt. [[FanNickname "Extra-Man"]] Ayala. Ayala appears in 120 episodes out of 167, in all seven seasons. He speaks in exactly four of those episodes, and is only credited twice, never with a name. The mere act of establishing a name for the actor took some detective work. He's achieved a certain amount of MemeticBadass status among the fandom for simply managing to surviving all seven seasons.
** The Gorn are a whole ''race'' of these - towering, reptilian aliens who were the primary focus of the Original Series episode 'The Arena', and had brief cameos in an episode each of the Animated Series and Enterprise. Despite these obscure beginnings, they crop up astonishingly frequently in games and other supplementary material, even becoming a playable race in VideoGame/StarTrekStarfleetCommand and VideoGame/StarTrekOnline.
* Rodney [=McKay=], who after a couple one-shot appearances on ''Series/StargateSG1'', became one of the main characters in ''Series/StargateAtlantis''.
** [=McKay=] is kind of a backwards case. The original Casting Call asked for someone with similar qualities to the [=McKay=] character. David Hewlett auditioned and nailed the part, at which point the producers [[ThrowItIn just turned the character into McKay]] since it didn't make much sense for David Hewlett to be playing a [[{{Expy}} similar but distinct character]].
** Also, Dr. Carson Beckett was originally only written into a few episodes throughout season 1, but he was such a big hit that the writers put him in several more. In later seasons, he's promoted to one of the main characters.
** Major Lorne appeared in a single episode of ''SG-1''. Starting from season 2 of ''Atlantis'' he became their ColonelMakepeace.
** Walter aka ({{Engaging Chevron|s}} Guy). Something odd as he never really gets a main character spot. He does get a big nod in the end of the 200th episode. However in the fandom, Walter (and his actor) have been used as stars in promos and skits. A promo for the aforementioned 200th episode has him going to ask his castmates, producers, writers and directors for his part on the special, only to realize none of them recognize him despite him having been on the show since the pilot.
** Vala in ''Series/StargateSG1'', who progressed from single-episode guest star in Season 8, to recurring guest in Season 9, to full-time cast member in Season 10.
* Parodied in a Ferrell-era sketch on ''Series/SaturdayNightLive'' with NBC making an adaptation of the [[Literature/TheBible New Testament]]. As they don't have time for a script, they just ad-lib (something that Creator/WillFerrell, playing Jesus, doesn't feel comfortable doing). When the actors can't decide how their characters should know each other, they just say they have a mutual friend named Barry. By the end of the sketch, Barry gets an "actor" (one of the boom-mike guys), ''Jesus'' betrays Barry, and (the film now taking place in a college dorm) Barry kills the Devil.
** Speaking of ''[[Series/SaturdayNightLive SNL]]'', {{Eddie Murphy}}.
** This seems to be SNL's policy regarding Featured Players: they are billed after the reperatory cast, and generally get less screen time, and if they manage to make enough of an impression to stick around for two years, they are promoted. For some, like Eddie Murphy above, or Amy Pohler, they are so well-liked that they are promoted early, even midway through their first season.
* ''Series/BuffyTheVampireSlayer'':
** Harmony was originally one of Cordelia's cronies who was in the second half of the pilot and got bitten by a vampire at the end of Season 3. She shows up again in Season 4 as Spike's vampire girlfriend. She later showed up in the Buffy spin-off, ''Series/{{Angel}}'', eventually promoted to main character. Actress Mercedes [=McNabb=] is the only actor in the Buffy franchise to go from extra to recurring cast member to regular. She also holds the distinction of being the only character (and actor) to be part of the Buffyverse for its entire television run, appearing in both the original unaired pilot and the last episode of ''Angel''.
** Danny Strong was credited as an unnamed extra on "Buffy" for quite some time before even "obtaining" the name "Jonathan". He became a minor recurring character and [[BigBadDuumvirate one of the three main villains]] in season 6. And in Season 7 it got to the point that The First thought him important enough to be included in its evil plan.
** Anya; she was originally intended as a one-shot villain for "The Wish."
** ElizaDushku's Faith originally started out with a planed minor role in the series, similar to Kendra's, but both the audiences and Joss Whedon became fans of Eliza and her character and she became a much more important to the story.
** Amanda first appeared as a girl getting advice from Buffy while she worked as a school counselor, but later was revealed to be a potential Slayer.
* Gonzo first appeared in the JimHenson and Ed Sullivan ChristmasSpecial ''The Great Santa Claus'' switch in a small role as a creature living in the villain's cigar box named Snarl. The puppet was repurposed for usage on ''TheMuppetShow'' and the rest is history.
** Ratzo Rizzo was also a minor character originally, going on to fame and fortune as Gonzo's sidekick. And Ms. Piggy, as originally conceived, was meant to be a bit player.
** ''Series/SesameStreet'''s Elmo was originally a nameless background character, but after Kevin Clash took over the role, he became a more regular character, and eventually received a recurring 15-20 minute sketch.
* ''FamilyMatters'': Harriette Winslow, the elevator operator at the Chicago Chronicle, was originally a recurring character on ''PerfectStrangers'' (a comedy starring Mark-Linn Baker and Bronson Pinchot), usually to give one-liners or provide superficial support to the storyline at hand. Then, her husband, Carl (a police officer with the Chicago Police Department) began appearing a couple of times ... and soon enough, someone got the bright idea that Carl and Harriette and their family (the children were referred to a couple of times) might make an interesting program. Hence, ''Family Matters''.
-->During the course of the series, several one-time minor characters were ascended to starring roles, virtually taking the emphasis completely off the Winslow family's dynamic in the process. However, much of this had to do with how well the actors playing these roles went over with the audience:
** Steve Urkel, the quintessential nerd, is the most famous example. The irksome Urkel was introduced as a single gag character in the episode "Laura's First Date" (aired December 15, 1989), meant to highlight just how bad an idea it was for the well-meaning Carl to find his dateless daughter Laura a date for a junior high dance at the last minute. (Laura later realized that the guy she ''did'' want to ask out was merely shy and had trouble asking her out, but that's beside the point.) By the end of the first season, Urkel was appearing in every episode, and when the first episode of Season 2 aired in September 1990, Jaleel White was given billing alongside the rest of the cast.
** Waldo Faldo. Also introduced midway through the first season, in the episode "The Party" (aired February 2, 1990). One of the many guests at Eddie's house party (held without his parents' permission when they're not home) is a "Boy in Towel." The "Boy in Towel" was a background character who showered in the Winslows' shower and acted like an idiot. Just like Waldo did late that fall ... when he was given his name and semi-regular status. By Season 3, Shawn Harrison's portrayal of the character was so popular he earned his spot in the opening credits and began appearing in virtually every episode.
** Myra Monkhouse. Like Urkel and Waldo before her, Myra was meant to be a one-time diversion for Urkel so that her cousin -- who happened to be Laura's boyfriend, Ted Curran -- could have her without interference from Urkel. Ted was dropped a couple of episodes later. Myra remained for almost the entire rest of the series (until Michelle Thomas fell ill with her ultimately fatal illness in early 1998) and was given full billing.
* Thanks to ''The Next IronChef'', Michael Symon, initially a challenger on ''Iron Chef America'' , ascended to a position of Iron Chef. [[spoiler:In season two, Jose Garces, who had defeated Iron Chef Bobby Flay, joined him.]]
* ''Series/BattlestarGalacticaReimagined'' had several characters who initially appeared in one-off or recurring roles, only to gain greater prominence in later seasons:
** Helo was intended to be a one-shot character from the miniseries, who was assumed to have died offscreen after giving up his space on Boomer's Raptor for Baltar. However, the producers not only brought him back, but his B-plot in the first season (traveling around Caprica with Sharon) becomes pivotal to the entire resolution of the series.
** Louis Hoshi starts out as a rarely-seen communications officer on the Pegasus. He gets more and more appearances in later seasons, eventually taking up [[spoiler:Dualla's job after her death]]. By the time the series finale rolls around, Hoshi is given the role of ''Admiral of the Fleet' by Adama after his team leaves to go on the rescue mission, solely because he is essentially the only other capable command officer left to run the ship.
** Captain Kelly starts out as a minor character who mans one of the flight pods in the miniseries, then later shows up for two episodes in the second season to help the command staff after Bill Adama is shot. He later gets a major role as the bomber during the trial at the end of the third season, and even had a redemption arc/HeelFaceTurn in season four during the mutiny onboard Galactica.
** Racetrack was intended to be a one-shot character who would appear in the final episode of the first season. However, Leah Cairns' performance impressed the producers so much that Racetrack essentially became the de facto Raptor pilot shuttling major characters around for most of the series, and she later became a ChekhovsGunman by [[spoiler:posthumously destroying the Cylon colony with nuclear missiles in the series finale]].
* In ''Series/DoctorWho'', the character of Wilfred Mott was initially a brief 2-minute cameo for Bernard Cribbins in the 2007 Christmas special. However, due to the death of the actor playing Donna's father, the character later returned as her grandfather in the 2008 series. His role continued to be increased to the extent that he was promoted to main companion status for the 2009 Christmas and New Year's specials, [[spoiler:and caused the Doctor's regeneration]]. Not bad for what was intended as a ''HeyItsThatGuy'' moment.
** Donna, who appeared in the [[{{ChristmasEpisode}} Christmas Special]] following series 2 and then later became The Doctor's companion for all of series 4.
** Rory Williams had a minor role as Amy's kind of boyfriend in "The Eleventh Hour". By "The Vampires of Venice" later that series, he became a full-ish companion, who was PromotedToOpeningTitles from "A Christmas Carol".
** From the classic series:
*** Jamie [=McCrimmon=] was supposed to be a one-off character for ''The Highlanders'', but the team liked him so much that they re-filmed the ending of the serial to keep him. He ended up becoming ''the'' longest running companion, appearing in all of the 2nd Doctor's stories apart from ''The Power of the Daleks'' and ''The Three Doctors''.
*** Colonel Lethbridge-Stewart from ''The Web of Fear'' was supposed to be a one-off character. Then they decided to bring him back for ''The Invasion'' and [[TheBrigadier gave him a promotion]], and he became one of the most important characters of the Third Doctor's era, and quite possibly the entire series. If you include multi-doctor episodes like "The Five Doctors", he appears alongside every doctor of the original series, and is mentioned by name by the 10th and 11th doctors. And in the Expanded Universe he has met 8 and 10. Even when the actor died his presence is still felt by his daughter Kate.
* ''Series/{{The Vampire Diaries}}''
** Vicki, Elena's aunt Jenna, and arguably Caroline. She had a fairly large role in the books, but on the show she's an entirely different character.
** Elijah as an extreme example. Julie Plec admits that Daniel Gillie's performance and the pull of Elijah's character inspired the writers to make the Originals un-killable to keep him around. And he was originally just a "foot soldier" before being made into Klaus's brother.
* Toshiko of ''Series/{{Torchwood}}'' was seen ever-so-briefly in series one of the new ''Series/DoctorWho'' first. As an extra, she was a doctor. As a full time ''Torchwood'' character, she was explained to have been impersonating a doctor because the actual doctor (fellow Torchwood member Owen Harper) had been too hung over to work.
* An extreme example of this is Mrs Miggins from ''Series/{{Blackadder}}''. In the second series she was an unseen character mentioned two or three times as a throwaway joke. She became a regular character in the third series.
** Although it couldn't be the ''same'' character, seeing how the two series are set centuries apart. It depends whether you regard the successive {{Blackadder}}s, [[BumblingSidekick Baldricks]], etc. as essentially the same character - which they are really, just reincarnated as [[IdenticalGrandson suspiciously similar descendants of their predecessors]], forever linked down through history...
* ''Series/RedDwarf'' has various examples. Kryten was a one-episode character who wouldn't have been included originally as one of the writers wanted to avoid robotic characters. He returned in Series III as a main character (although played by [[TheOtherDarrin a different actor]]).
** Kristine Kochanski was a minor character from Series I, II and VI who appeared in the first half of the first episode, [[PosthumousCharacter died, and thereafter was relegated to flashbacks, stasis leaks, shape-shifters and anecdotes by the main characters]]. She became a main cast member in Series VII, again played by [[TheOtherDarrin a different actress]].
** Captain Hollister, another first-episode character and [[PosthumousCharacter posthumous flashback regular]] from the first two series. He was brought back for Series VIII, in which he appeared in all but one episode. Unlike Kryten and Kochanski, the same actor portrayed the Captain.
* ''Series/{{Glee}}'' seems to live off of this, especially in the second season.
** We'll start with Brittany, though technically she ascended in the first season. Heather Morris was a back-up dancer for Beyonce's "Single Ladies" live performances and was initially hired to teach the choreography to the cast. They gave her the role, intended to be just a recurring background dancer, without even an acting audition. It turned out that she had great comic timing, and after a gradual increase in lines over season one, she was promoted to the regular cast by season two, and is also a major player in one of its subplots.
** Similar to Britanny, Santana was little more than a background character in the first few episodes only getting a few lines here and there but eventually started getting more and more focus, probably due both to actress Naya Rivera's ability to sell the part of bitch real well and her chemistry with Heather Morris making them a great comedic duo.
** Mike Chang went from a minor character in season one to getting more and more focus in season 2. His actor Harry Shrum will promoted to main cast member in season 3.
** Dave Karofsky. He was a two dimensional, stereotypical, homophobic highschool bully but has now been promoted to [[ArmouredClosetGay having his own]] [[ComingOutStory sub-storyline.]]
** Lauren Zizes was a randomly-appearing homely looking girl who most fans and characters didn't bat an eye at. Suddenly, halfway through the second season, she became an EleventhHourRanger, Puck's new love interest, and an extreme Badass in one fell swoop.
* In ''TheSookieStackhouseMysteries'' novels, the character of Mary Ann [[spoiler: originally named Callisto]] pretty much just showed up at a party, made a few comments and was never seen again. On TrueBlood, the show based on the books, she was the BigBad of season two.
** Similarly, Lafayette Reynolds has been a pretty prominent supporting character since the show began, but appeared only briefly in book one before [[spoiler: being killed off at the beginning of book two]].
** Tara, Lafayette's cousin, wasn't even mentioned in the first novel, but she is Sookie's best friend through the whole series.
* Paul from ''Series/{{Cheers}}''. But not as much as Series/{{Frasier}}, who went from just another bar patron to a main character, to the star of his own SpinOff.
** Actually, Frasier was a guest star who was only intended to be a RomanticFalseLead who would vanish after ''one season''. He was so popular, he stayed for nine seasons on ''Cheers'' and did another ten on ''Frasier''.
* Becker in ''{{Primeval}}''. Originally just a [[MauveShirt named redshirt]]. Now a main character with, apparently, his own love interest.
* Gunther in ''Series/{{Friends}}''. He was originally an extra appearing in the background of a few Central Perk scenes. The show's executives decided to give him a named role in Season 2 because he was the only extra who actually knew how to work the coffee machine. He became a bigger regular after Season 3, when his character was given a hopeless crush on Rachel as a RunningGag that would continue for the rest of the series.
* Benjamin Linus from ''Series/{{Lost}}'' was only supposed to appear in three episodes in season two, but the writers liked him so much that they rewrote him to become a major character in the series.
** The exact same thing happened to Desmond, a three-episode guest star in season two who became an important regular in the subsequent four seasons.
** The writers tried to create an illusion of AscendedExtra for [[TheScrappy Nikki and Paolo]] by pretending that they were "there the whole time, but weren't being focused on" when they were introduced in season three.
* ''Series/OnceUponATime'' has Belle who only appeared in three episodes for the first season and was upgraded to a main character in the second season.
* The Zyu2 monsters for the first and second seasons of ''Series/MightyMorphinPowerRangers'' are kind of this trope. The ''SuperSentai'' footage was exhausted by "[[SeasonFinale Doomsday]]," so {{Saban|Entertainment}} contacted Toei to produce more action footage to keep the season/series going, and the [[FanNickname Zyu2]] episodes were shot with monsters and battle footage [[AdaptationExpansion exclusively for the US series]]. Starting with Goo Fish and finishing with Turban Shell, each of them started as a MonsterOfTheWeek like any other. Since they were US-only monsters, Saban owned the costumes exclusively without having to rent them. As Saban had to fill out the 50-episode second season, bringing back hordes of old monsters became a fairly regular occurrence as the season wore on, and most (if not all) of those monsters would be from the Zyu2 crowd. Some even showed up for the grand season 6 finale at the end of ''Series/PowerRangersInSpace'', and even the monster hell scenes from the final arc of ''Series/PowerRangersLightspeedRescue,'' (season ''eight.'') Of course, these scenes contained many monsters from across franchise history, American-original ''and'' Japanese-original.
** Season two had Zedd summon some past monsters to protect the Rock of Time... ''immediately'' followed by past monsters being involved in the wedding of Rita and Zedd. Some of them were the same ones. This meant we had one-shot monsters from ages past returning for ''four episodes in a row.'' Dramole in particular totals ''six'' appearances in which he actually does something (not crowd filler like in Countdown.) Undoubtedly a record for ''most'' {{Toku}} (the ''Franchise/UltraSeries'' has some iconic recurring monsters too.)
* The British TV Show ''{{Skins}}'' has a great example in Effy, who was the little sister of her main character Tony for series 1 + 2, but appeared in only a few episodes and never spoke. When the new cast was picked for series 3+4, Effy was promoted to a full character and became the main protagonist. Effy remains the only character to be involved in more than three series of skins. (Pandora briefly appears in Series 2, before being promoted to full cast in 3)
* Zack Allen of ''Series/BabylonFive'' didn't even rate a name in his first several appearances, being just another faceless security guard. By Season 4, he had been promoted to the opening credits.
* Archie Kennedy, as well as Styles and Matthews, from the HoratioHornblower mini-series. The latter two characters were mentioned in the first book briefly, but given no real importance, and in the series they're promoted to ThoseTwoGuys and prominent lower-deck characters. Archie is somewhere between this and CompositeCharacter, as he is mentioned by last name in the first book, but his personality is made up of fragments of other minor characters from the books. Still, he goes from being a midshipman who appears in one scene to being the title character's best friend -- a definite step up.
* Richardson in ''{{Series/Deadwood}}''. The actor was hired as an extra and eventually placed as Farnum's cook. The writers gave him a few incidental lines and liked the results, so he was expanded to a fully-fledged supporting character.
* On ''BoyMeetsWorld'', Angela first appears in season 5 episode 2 as a student in Feeney's class who has one line of dialogue, and then in season 5 episode 7 she has a much larger role as Shawn's girlfriend and from there she becomes a recurring character and then a main character.
* Several initially-unimportant characters in ''Series/TheWire'' gain greater prominence as the series goes on:
** Probably the most notable example is Kenard, who is introduced in a very short scene from the third season where Bunk Moreland sees him and two other children arguing over who will pretend to be Omar. In the fourth season, he gets more dialogue and scenes with the neighbourhood children, and in season 5, [[spoiler:he is the one who shoots and kills Omar in a convenience store]].
** Detective Colicchio was initially an unnamed background character in Major Colvin's unit before gaining an abrasive personality and more dialogue.
** Jeff Price (a court reporter for the Baltimore Sun) appears in one season three sequence (a press conference) asking a question, then becomes a full-fledged supporting character in the fifth and final season.
** A young woman is seen as an extra during one sequence in Hamsterdam from the third season, has a couple lines of dialogue during a scene with Old-Face Andre in season 4, then is shown at a recovering addicts' meeting Bubbles is attending in season 5.
* Ronnie Gardocki from ''TheShield''. The character was initially treated as a glorified extra, and the only reason why actor David Rees Snell took the part was because creator Shawn Ryan needed someone to fill out the team. You could count the number of lines Ronnie had in the first season ''on one hand''. Yet, as the seasons continue, Gardocki becomes more and more central to the power struggle between Vic and Shane, and becomes a fully-developed main character in his own right.
* Dr Vincent Strudwick from ''ThirdRockFromTheSun'' became Dick's SitcomArchNemesis in the later seasons.
* Both Al and Heidi on ''HomeImprovement''. Al was originally a temporary character because the producers were waiting out for another actor to play Tim's assistant on ''[[ShowWithinAShow Tool Time]]'', but that didn't go through and they made Al a permanent character. Heidi's role on ''Tool Time'' was expanded from just introducing Tim and Al and helping bring out tools to having a part in the projects on the show, and she was given more screentime outside of ''Tool Time'' which included a few storylines about her personal life.
* ''Series/{{Community}}'' has quite a few example of one time characters being brought back for later episodes. Leonard is a pretty prominent example.
* ''MysteryScienceTheater3000'' - Pearl Forrester was initially a very minor character who showed up occasionally for some jokes at her long-suffering son Clayton's expense. When Frank left the show before the abbreviated seventh season, Pearl moved into Deep 13 permanently, though she was still used mainly for mother jokes and wasn't really a villain. Then the show was resurrected sans Clayton and Pearl became main antagonist for the remaining three-year run.
* Sir Leon from ''Series/{{Merlin}}'' was originally just an extra who was chosen to speak on behalf of the RedshirtArmy of Camelot knights. He proved so popular with both the cast and the audience that the writers brought him back after he was seemingly killed off, and upgraded him to Arthur's second-in-command.
* Kari Byron made her first on-camera appearance in a ''pilot'' episode of ''Series/MythBusters'', for the vacuum toilet myth. ([[ItMakesSenseInContext She had her rear end scanned]].) She reappeared, alongside fellow Build Team members Scottie Chapman and Tory Belleci, at the beginning of the second season.
* Jimmy Palmer of ''Series/{{NCIS}}'' started in the middle of the first season as a replacement for largely identical character. In Season 6 he was promoted to "Also Starring" and in Season 10 he is promoted to a series regular.
* ''Series/{{JAG}}'': Petty Officer Jason Tiner (played by Chuck Carrington), the Admiral's yeoman, went from an extra and became a minor character in his own right after a few seasons, and apart from the lead characters, appeared in the highest number of episodes.
* ''Series/{{Supernatural}}'': The [[LastEpisodeNewCharacter final episode of the first season]] introduced Bobby Singer, a hunter who'd worked with Sam and Dean in the past. He shows up at the very beginning to help them out against Meg and then disappears for the rest of the episode. Come season two, Bobby's back aiding the boys [[spoiler: after their father's death]] and goes on to become a father figure to them who's pretty much the most important character on the show next to the boys.
** When Castiel was introduced in Season 4, he was only meant to last a few episodes. But due to positive fan reaction, he remained as a recurring character in Season 4, was upgraded to a regular in Seasons 5 and 6, downgraded to recurring for Seasons 7 and 8, and has been announced as a regular for Season 9.
** Crowley appeared in the fifth season, one that was originally intended to be the final one. He first appears briefly in the middle of it, then doesn't show up again until the tail end of it, both times providing some aid for the boys against the much worse antagonist [[spoiler: Lucifer]]. Then the show [[PostScriptSeason continues going after that]] but there's one problem: now that your BigBad for the entire series up to that point is out of the picture, who do have take his place? That's when Crowly returned front and center and went on to become the show's primary antagonist, even getting promoted to a regular for Season 10.
* ''Series/TwentyFour'':
** In the first season, Glenn Morshower played Agent Aaron Pierce, a member of David Palmer's security detail. He originally had very few lines, and mostly stood around in the background of shots while Palmer did campaign speeches. However, his importance grew in subsequent seasons - in the second, he has a plot arc where he betrays the President and subsequently apologizes. The production crew were planning to kill him off in season 5, until Morshower's performance in a late-season episode impressed them so much that they hastily changed the script to keep him alive. He would then go on to have further appearances (and even helps Jack during the siege on the White House in season 7), and is one of only 4 characters from the first season to have survived through the entire series.
** The sixth season introduced a relatively minor character named Ethan Kanin who was the Secretary of Defense. He briefly shows up a couple times to talk about a few decisions regarding the current President and overall was pretty forgettable. Then Redemption and the last two seasons come in and he becomes the Chief of Staff under the new President often acting as her only real confidante during some of the harsher moments on the show.
* ''Series/TheOfficeUS'': A lot of characters qualify as this. Basically everyone except Michael, Dwight, Jim, Pam, and Ryan. In the first season, much of the supporting cast were basically extras who didn't have any storylines or personality traits until season 2.
* ''ThePriceIsRight'' has always had the game show staples of LovelyAssistant (a rotating cast of models) and TheAnnouncer. But early on, the models just showed off prizes, and the announcer just read copy. After a few years, both the models and announcer began interacting with host Bob Barker a lot more, usually conversing with him between segments, being shown on-camera more, and even participating in humorous skits during the Showcases at the end of the show. The interaction died down some in the 1990s and 2000s, but came back in the late 2000s after Drew Carey took over as host.
* Similar to the ''Series/{{Friends}}'' example, in ''[[SieteVidas 7 Vidas]]'' Gonzalo de Castro just played the waiter at the bar the main characters went to, but soon became a main character and stayed in the series until the last chapter.
* In Series/TheSopranos, Adriana La Cerva, the girlfriend of Christopher Moltisanti, originally appeared in the series pilot as an unnamed hostess at Artie Bucco's restaurant with just a couple of lines. However, producers of the show were so impressed by what they saw of Drea De Matteo's acting skills, that she was quickly promoted as Christopher's love interest and a major character in the show.
* On the 1970s ''Series/BeatTheClock'' revival, announcer Gene Wood was the celebrity partner for a week, with Nick Holenreich taking Wood's usual role. After Jack Narz stepped down from hosting in 1972, Wood was promoted to the hosting position, and Holenreich became the permanent announcer.
** Promptly inverted on the 1980 revival, which had Narz as announcer and [[LetsMakeADeal Monty Hall]] as host.
* Tobias Gregson was an extremely minor character in the original ''Literature/SherlockHolmes'' stories, but Captain Gregson is a major character in ''Series/{{Elementary}}''. He essentially fills the role usually held by Lestrade in the original stories and most adaptations.
* Ruthie Cohen, played by extra Ruth Cohen, on ''Series/{{Seinfeld}}''--the cashier at Monk's Cafe. Appeared in 101 episodes of the series, more than twice as many as Newman! Ascended to actually speaking lines in two episodes, and was a central character for one. Also appeared as the cafeteria cashier on ''{{NCIS}}'', referencing her Seinfeld role.
** Harshly subverted with Babu Bhatt, who in his second appearance shows every sign of being promoted to a recurring character by working at Monk's and living in Jerry's building. Then he's deported. In the DVD special features, Brian George recounts his experience reading the script, and the sharp emotion switch upon realizing this would be it for him.
* Aída started as Sole's cleaning lady in ''Siete Vidas''. Her character was so interesting she was soon made a regular and given a job at the local pub. She eventually got her own spin-off, ''Aída'' which survived the main series for over a decade (and, as of July 2013, is still going).
* ''Sukar'' was suppossed to be a one off character in {{Series/Defiance}}. However, the creators were impressed by the contributions that Noah Danby made in defining the ''Irathient'' race that he was was written into more of the stories, and eventually ascended to a SacrificialLamb.
* ''Series/PersonOfInterest:''
** Root was originally intended to be a VillainOfTheWeek, but has become central to the main StoryArc and will be a regular in Season 3. Jonah Nolan explained why [[https://www.personofinterestdiscussion.com/node/1728 in an interview:]]
-->We knew we wanted to see more of the character Root as soon as we heard [[AwesomeMusic the incredible theme Ramin cooked up for her in her first appearance]].
** Detective Tierney had bit parts in a number of episodes throughout seasons 1 and 2, mostly as just another face around the 8th Precinct, but the final scene from "All In" paved the way for him to become a more significant character.
* A character, played by Martin Clunes appeared in a film ''Saving Grace'' and later two prequel miniseries. In making ''Series/DocMartin'', the character was given a ReTool with DoctorJerk added to the character (who was originally just a FishOutOfWater), and his last name was changed to Ellingham (an [[SignificantAnagram anagram]] of the last name of the show's writer Dominic Minghella).
* On ''{{Series/Degrassi}}: The Next Generation'', some minor/recurring characters have been upgraded to regular cast [[RevolvingDoorCasting as some of the characters get older and graduate.]] For example, Clare was originally introduced as a minor character, the middle-school aged sister of one of the main characters who appeared only a couple of times. She became a main character beginning with season 9-10.
** Emma originated in ''Series/DegrassiJuniorHigh'' as [[TeenPregnancy the daughter of one of the characters]] (who was also an Ascended Extra). When the franchise got a SettingUpdate (''TNG''), she became one of the main characters.
* [[TheCoroner Max Bergman]] was originally just a one-episode test character on ''Series/HawaiiFive0''. He proved likeable enough that he now shows up about OnceAnEpisode, usually to autopsy a body but also to celebrate with the gang after a case. [[HeyItsThatGuy Being played by]] Creator/MasiOka of ''Series/{{Heroes}}'' fame probably helped.
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