A Father to His Men: His paternal leadership style, especially visible with Greg, Nick and Warrick especially right before Warrick gets killed, and afterwards.
Flanderization In regards to his stoicism. In the first season, he was prone to bouts of anger (once slapping a coffee pot out of Ecklie's hand, enraged) and happiness (even—gasp—smiling! With teeth and all!). By Season 3, his character was shaped into being level-headed at all times, even in normal conversation. Justifiable in that he starts to retreat emotionally during his struggle with his hearing loss.
Intelligence Equals Isolation: Especially in the earlier seasons. Despite his intelligence and expert grasp of human nature, Grissom lead a very isolated life, and rebuffed most opportunities of interaction outside of the workplace. He even turned down Sara's initial dating requests in Season 3.
Married to the Job : For most of the series, at least until he married Sara. Catherine used to tell him to take his head out of his microscope once in a while.
Nice Hat: Seen sporting a straw sunhat in more than one episode. It was once complimented by a hooker.
And that hat belongs to Petersen himself acquired from his own travels.
Serious Business: Racing cockroaches. One of the first time we see him take some time off and puts Catherine in charge is when he goes to a conference to race his vermin. It doesn't go so well ("Stage fright.")
Silver Fox: Despite his nerdiness and aloofness, he still gathers a lot of female admirers (in-universe and out), even when he shies away from the unwanted attention.
Heroic Bastard: It's established early on that she was raised by a single mother, but it's only later that she learns her father is Sam Braun, who leaves her a chunk of his casino after he dies.
Mama Bear: Messing with her daughter? Big mistake. The same applies to her team members
Ms. Fanservice: She used to be a stripper, way back in the day (and not an Old Shame for her, even when a DA tries to use it against her in court). She's had a couple of Toplessness from the Back scenes and an interrogation where she unbuttoned her blouse every time her suspect gave her an answer.
Revenge Before Reason: Her automatic hatred towards registered sex offenders and anyone she even suspects of being a child abuser.
The long version: Catherine has several times had a very strong reaction to cases where a little girl is the victim of their case, to the point where she will allow her own emotions to cloud her judgement. It is hinted this is because she is the mother of a young girl. Her emotions have caused her to severely jump the gun when it comes to a suspect and showing no hesitation to add her own verbal disgust and disbelief towards a suspect when they tells her their side of the story. Sara even once lampshaded this by snarking that it was "fun" to hear Catherine's theories rather than process the actual evidence. Ironically, every time she has let her emotions take control of a case like this, who her hatred is focused towards has always turned out to be a mere victim of "being at the wrong place at wrong time", shown by the evidence they were in no way involved with the case, but by the time that is revealed she often has completely ruined said guy's life.
Brutal case and point being Leo Finley from "A Thousand Days on Earth". She believed he was a child molester because of his name on the Sexual Predator Watch List though he was only there because of an incident where he got high on hallucinogenics and walked out naked in front of a bus full of children. After the man's fiance found out about his past (through Catherine vindictively outing him) and that he was using an assumed name, she kicked him out of the house and then got him fired by telling his boss. The man walked up to Catherine in the parking lot after this, threatening to shoot himself in the head on her front lawn one day, even calling her a "blonde Nazi bitch" when she insists she was just doing her job.
Scare 'Em Straight: In response to Lindsey's reckless hitchhiking, her mom drags her into the morgue to view a dead hitchhiker (to Dr. Robbins' disapproval).
Ship Tease: With Warrick, up until his marriage. She even referred to the event as the "end of a fantasy".
Hint Dropping: Tries this as a tactic while trying to court Grissom. She once told Hodges (who was fretting about a possible grey hair) that she finds grey hair rather sexy, while standing next to Grissom. Eventually, she point-blank asks him out, which he refuses. After a couple of more years, he eventually comes around to Glad You Thought of It.
Genius Ditz: In earlier seasons. While he does act like an idiot he's very good at his job, and has extended knowledge on coin collection and Old Vegas.
I *Might* See Dead People / Maybe Magic, Maybe Mundane: His grandmother had "the Sight" and the psychic who sensed his grandma tells him he has it too. One the one hand he couldn't detect anything when he was in the "haunted" slaughterhouse with the killer, on the other one could argue the spirits were being really quiet so he could hear the killer's ringtone, which was caught on tape by the psychic before she was killed.
Freudian Excuse: Played with. His father was apparently violent, and Raymond worries that he may become that way himself. He also has a gene that has been associated with violent behaviour. On the other hand, when faced with Serial Killer Nate Haskell, who has the same gene and his own abusive father, he testifies in open court against his attempt to use this card, and afterwards Haskell admits to him that he decided in his youth he'd blame it on those things if he were ever caught.
Team Dad: Picking up where Grissom left off, but in a different kind of way since D.B. is a literal father as well. He's especially this trope for Greg and Morgan, the two youngest CSIs. (Morgan's actual father, Ecklie, practically states this trope directly in CSI Down.)
True Companions: He regards the CSI team as this. They're a little weirded out by it.
Absolutely has this with Hodges. They bicker frequently, but clearly care about each other. Morgan actually flat-out refers to him as her best friend, and even once agreed to pretend to date him in order to get his mother off his back. (And now that her father is dating his mother, well, both the bickering and the caring have gotten more interesting.)
Handicapped Badass: He might need a cane to get around, but he can be a pretty mean fighter when he has to be.
The Lab Rat: Sort of, although he's a mortuary rat rather than a lab rat.
Mr. Exposition: His autopsies often reveal further background on the murder victims.
Sympathetic Adulterer/Your Cheating Heart: Reveals in season 12 that he cheated once, essentially just to see if he had the guts to. It nearly ruined him and his wife, and they've been faithful ever since. It's really kind of adorable.
Momma's Boy: He was living with his mother when he first started working at the lab. When she finally appears on-screen, we learn that she's a surprisingly attractive and classy lady, and far from the typical My Beloved Smother that most mothers involved in this trope are.
Pet the Dog/Establishing Character Moment: For the first couple seasons he was on the show, he was portrayed as a through-and-through JerkassProfessional Butt-Kisser with no redeeming qualities whom all his co-workers hated. In Season 7, however, he gets a surprising amount of Character Development in a scene where he has to break the bad news to a victim's family, and he's been portrayed as a sympathetic character ever since and even joined the main cast.
Deadpan Snarker: On Vegas' staggeringly-high murder rate: "We're very competitive!"
Dirty Cop : Originally a big subversion of this, stating how he refused to be bought or get dirty, but now drifting into that territory as of the end of season 11. He covered for Ray when Ray killed Nate Haskell, and was reluctant to help catch a killer who was killing other killers.
Et Tu, Officers?: In the episode, "A Bullet Runs Through It", he felt this way when one by one, all of the other officers walk away from him at the dead officer's funeral.
A Day in the Limelight: The B-plot of one episode featured Ecklie handling the investigation himself when the main characters were unavailable.
Ambition Is Evil: The real reason he was such an ass to Grissom and the team was because he thought that Grissom had the same ambitions he did. Once he realized that Grissom and the team wouldn't keep him from fulfilling his goals, he eased off considerably.
His behavior in the season 14 episode "Consumed," though, suggests that running for sheriff may cause him to relapse.
Big Bad: Arguably, of season five. He never does anything illegal, but his antagonistic actions drive the overarching plot of that season.
Character Development: A fairly significant example of this. He's almost a completely different person now than he was in season 1. He makes a pretty seamless transition from Jerkass to Jerk with a Heart of Gold. After 13 seasons he's still can be a bit nasty at times, but he has the respect of the team and the department as a whole, and he's absolutely a Reasonable Authority Figure now. (He's aware of it, too: when he talks to Morgan about being offered the sheriff position, he admits that part of the reason he isn't sure about it is because he's afraid he'll revert to the manipulative asshole he used to be.)
Da Chief: He starts out as the day shift supervisor, then becomes director of the lab, and is later promoted to undersheriff of the entire department.
Come mid-Season 13 he's the new sheriff. He almost didn't take it at first, because he was worried that he'd revert to the Jerkasshe used to be.
Jerk with a Heart of Gold: Developed into one, and a Reasonable Authority Figure, pretty nicely afterwards. His statement that he would've helped Grissom and Sara avoid any conflicts because of their relationship certainly sounded genuine, and he's been mostly a lot nicer to the team while still keeping his prickly attitude. Come the later seasons, and he's been even better with Morgan around.
Obstructive Bureaucrat: He's extremely ambitious, and saw Grissom as competition. At different points, he would try and undermine the team's work.
Reasonable Authority Figure: When Nick was Buried Alive, Ecklie pulled some strings to gather the ransom his kidnapper, and relations between him and the night shift have mostly thawed since then. Ecklie came into his own as Asst. Director, where his talent for juggling the top brass and news media have proven to be an asset to the team.
Now he's the new sheriff, and he seems to have kept his reasonableness. The only time so far that he's really pushed back against the team is when he's faced with having to give permission for his own daughter to be used as bait for a serial killer. A perfect example of his reasonable attitude is when Finn and Nick clash with a fire investigator at an arson scene. The investigator calls in Ecklie with "concerns" about their methods, and before passing any judgements, Ecklie hears Nick and Finn out and even takes his jacket off and helps them dig through a burnt-out building to prove their theory.
The Rival: To Grissom, who deplores Ecklie's careerism.
Smug Snake: Pre-"Grave Danger." He took utmost pleasure in seeing Grissom's team humiliated, and even worked to get Nick convicted of murder once purely out of spite.
Taking the Bullet: For his daughter when he gets gunned down in Homecoming. It's possible that they had been aiming intentionally for him, but given that he shot McKeen's son, it seems likely that Morgan was the target.
Ambition Is Evil: Brass recalls that when he was made a detective, McKeen invited all of the new detectives over to his (suspiciously large) house for a barbecue. When Brass let him known that he wasn't such a careerist that could be bought like that, he was never invited again, and had to watch over the years as all the others at that barbecue were promoted above him.
Big Bad: Of Season 8, the 12 finale, and probably at least the premiere of 13.
Clueless Detective: Doesn't always get or appreciate the abilities of the CSI's or what they do which bites him in the ass when he tries to frame someone else for murder.
Playing Gertrude: Melinda Clarke was 32 when she first played the role of a character who, given her daughter's age, was probably intended to be in her early forties. Melinda wasn't even 40 by the time Heather became a grandmother in the show.
The Vamp: Used for good! In her third appearance, she sleeps with Leon Sneller, the guy who killed her daughter to get evidence from him to give the team.
Whip It Good: Used horrifyingly in "Pirates of the Third Reich" when she captures Sneller, ties him to her car, and proceeds to try to whip him to death. Grissom talks her out of it.
The Don: Gives off this impression, but nothing's ever proven beyond this.
Drop-In Character: It's apparently a small Vegas after all, because like Heather, his name comes up in a frankly absurd amount of cases. The difference, of course, being that while Heather usually takes the role of key witness, Sam being who he is is often the prime suspect.
Karma Houdini/Not Proven: He was a suspect in a murder from decades ago, and Catherine wholeheartedly believes it was him, but there was another suspect whom all the evidence seemed to point to and Sam is never charged.
Kick the Dog: Organizing the bank robbery that gets Detective Lockwood killed. Kept from being a full-on Moral Event Horizon-crossing by the fact that Sam didn't intend anyone to die and the Ax-Crazy head robber went off the rails, but the fact that he was willing to put innocent people and lovable supporting cast members in a life-threatening situation purely for his own benefit is a pretty huge dick move.
Morality Pet: Catherine. He also expresses genuine affection for Catherine's mother and Lindsay, but is never seen interacting with them on-screen.
Pet the Dog: Hates himself for favoring his older son, leading to the jealous younger one killing him.
Red Herring: No matter how good him motive or opportunity might've been, he is always this.
Freudian Excuse: He (or rather, "she" at the time) watched as his father was murdered and the death made to look like a suicide in his own home, and then his testimony was thrown out at the trial and the killers went free.
Pet the Dog: Revealed posthumously; he honestly loved his adopted son.
Secret Identity: As a judge, complete with a family who know nothing of his murderous ways.
Serial Killer: The series's first, and the setter of the standard for season-long arcs focusing on serial killers.
Series Continuity Error: A major plot point in his last episode is that he and his father have the same name... except that the elder Millander's name was given as "John" in a prior episode.
Transsexual: He felt the reason his father's killers went free after his testimony was thrown out was that he was a girl and therefore "weak," so he decided to become a man, though it was implied he had gender identity issues going further back than this.