Played by: Poppy Montgomery
- Action Girl
- All Women Love Shoes: She name-drops (and drools over) Louboutins in "Friended".
- Berserk Button: Don't hurt children around her.
- Beware the Nice Ones: She looks pretty nonthreatening . . . until you try to hurt an innocent person and realize she's a bit of a Cowboy Cop.
- Blessed with Suck: Her Photographic Memory makes her an excellent investigator but also means that she will never be able to forget any details of the grisly crimes she comes across. She also has issues with personal relationships since she cannot really "forgive and forget" when a relationship goes sour on her.
- Broken Bird: She's cursed to remember every day in its entirety, yet her mother has Alzheimer's and doesn't even recognize her most of the time. The one day she can't remember is the day her sister was murdered and she was there.
- Brought Down to Normal: In "DOA" she's poisoned with a nerve agent that interferes with her memory even as it's slowly killing her.
- Bunny-Ears Lawyer: In "Cashing Out" it turns out Eliot knew all along about her underground casino habit (even Al didn't know she was still visiting them) and let it slide on account of she's a damn good detective. He does, however, warn her to be discreet, since if word got out it would only hurt the Major Crimes squad.
- Cowboy Cop: To Al's everlasting irritation.
- Custom Uniform of Sexy: She always comes to crime scenes in tank tops and jeans, despite this being New York. The impropriety is discussed by Carrie and Al in the pilot, where Carrie admits that she's useful enough to get away with it.
- Fair Cop
- Fiery Redhead
- Insistent Terminology: She always tells people to call her Carrie, and introduces herself as such, rather than "Detective Wells".
- Kleptomaniac Hero: Her risk-taker streak gets the better of her in a Running Gag in "New Hundred". A Secret Service agent trying to break up a counterfeiting ring keeps getting out the new super-hard-to-counterfeit $100 bills, and Carrie keeps pocketing the real ones (and a bundle of the fake ones at the denouement, which Al puts his foot down about and tells her to throw on the bonfire with the others).
- Ms. Fanservice: She wears tight dresses more often than you'd think considering her job.
- Photographic Memory: The core premise of the show is that Carrie never forgets anything she experiences. A lot of emphasis is placed on the fact that she can go over a memory in her mind multiple times and reexamine it for details she missed originally. The ability is portrayed both as a great gift and a curse since she will always perfectly remember the best moments of her life but will also never forget the grisly details of the crimes she investigates.
Carrie doesn't just have photographic memory, but rather, Hyperthymesia, which is an explicit fact per the pilot. The difference between the hyperthymesia and photographic memory is that hyperthymesia tends to go "one step further": in addition to perfect recalling of images, senses including scents, sounds, taste, and the like, as well as events and conversations, are recalled with ease, whereas photographic memory is more often than not entirely visual. This is demonstrated in several episodes when Carrie can recall odors and muffled gun shots that allowed her to determine where they were shot from at the crime scene. As of now, a mere twenty cases of hyperthymesia are confirmed to exist.
- Sticky Fingers: She has a tendency to swipe money if she can get a chance.
- Tank-Top Tomboy: Among her Cowboy Cop tendencies is that she almost invariably turns up at crime scenes in a tank top and slacks, weather permitting. By contrast the female detectives in the supporting cast (Nina in season one, Murray post-retool) wear pantsuits.
- Unexplained Accent: She suddenly develops one in "Friended". Five episodes of a standard Midwestern accent, and in this episode, she has a noticeable Southern drawl.
- Working with the Ex: With Al.
Played by: Dylan Walsh
- Berserk Button: Don't threaten Carrie around him, or badmouth honest cops.
- Beware the Nice Ones: With a pinch of Crouching Moron, Hidden Badass.
- By-the-Book Cop: Although that kind of goes out the window in "With Honor" when his ex-partner is accused of being dirty.
- The Casanova: He has a lot of exes (one of the show's Running Gags is Carrie finding out about them and acting jealous), though he seems to have only dated one woman at a time.
- Fair Cop
- Nice Guy
- Working with the Ex: With Carrie.