NYPD 64th Precinct:
- Played by: Jennifer Lopez
- Action Girl: Comes with the territory of being a police officer.
- Anti-Hero: She doesn't like the idea of being a corrupt cop to help clean the streets, but she sticks to it if it helps.Harlee: You have no idea what it takes to be a good cop... You don't get it. Violent crime is down, drugs and gangs away from schools because of this unit, because of Wozniak.
- Bittersweet Ending: Harlee has to go to prison for a while and will also never be a cop again, so she asks Wozniak to take care of Cristina for her, but at least Cristina will be safe and Stahl is dead so he will no longer bother her.
- Dark and Troubled Past: Had an abusive boyfriend for many years before she framed him for a crime he didn't commit just to get away from him.
- Dirty Cop: One of the many in the 64th. And she's the protagonist.
- Experienced Protagonist: Been in the NYPD for a few years now, starting from being a uniformed officer.
- Fair Cop: Being played by Jennifer Lopez helps.
- Mama Bear: The reason why she's a Dirty Cop? To support her daughter. She reacts violently to any perceived threat against Christina, in no uncertain terms. This included putting Christina's father in prison for a murder he didn't commit so his abusive ways wouldn't affect her.
- Sanity Slippage: After her kidnapping by Stahl, she sees and hears things that aren't there. She ends up shooting a man after seeing Stahl's face on him.
- The Mole: Became the mole for the FBI in the 1st season.
- Weapon of Choice: Uses a Glock 19 as her main sidearm. Has a Smith & Wesson 3913 Ladysmith as her backup.
- Played by: Ray Liotta
The CO of the 64th Precinct. He had a stint in the USMC for 25 years prior to joining law enforcement. In charge of most dirty cops in the precinct.
- An Offer You Can't Refuse: Agrees to be a mole for the FBI in the 2nd season.
- Bi the Way: He's suddenly revealed to be romantically involved with another man (also a cop).
- Bitter Sweet Ending: He gets to have Cristina as part of his family, but Harlee will not be a cop under his command anymore and it's implied he is still going to be haunted by the hallucination of Anna-Kate.
- Cop Killer: Gets rid of Saperstein in "Undiscovered Country".
- Dark and Troubled Past: He lost his daughter to suicide after being treated for depression for some time. He couldn't get over it.
- Dirty Cop: In charge of dirty cops in the 64th.
- A Father to His Men: He looks after the crew seriously as if they were his family.
- Hero with Bad Publicity: While he's known for being a Dirty Cop, "Cry Havoc" ramps it up when Homeland Security gets a notice out that he kidnapped the son of a known cartel boss.
- Only in It for the Money: Matt tells Harlee that he wants to do the unsavory jobs outside of his NYPD duties to get enough money to retire and support his wife and himself and not to be a security guard.Matt: "I've got five years till retirement. I've seen these pension-strapped mopes working security in parking garages. I'm not gonna do it. I've worked too hard for that.Harlee: ...If we do this, you won't have to worry about your pension.
- Pet the Dog: Matt helps Harlee and her daughter, Cristina, once in a while. He even offers to help Harlee get her car fixed by asking the precinct's mechanic to help get it repaired.
- After he finds out that the others tried to kill Loman, Matt tries to let him know that he went through it and it's best to make peace with his mistake.
- Properly Paranoid: Once he gets suggestions that a mole was inserted into his unit, Matt thinks about subjecting everyone to polygraphs. He decided against it anyway since he taught everyone, including Harlee, to beat it.
- Played by: Drea de Matteo
A veteran police officer. She's trying to get her marriage working again with her husband.
- Action Girl/Dark Action Girl: Depends mostly on her work, but Tess mostly veers to the latter.
- Dirty Cop: Another one in the 64th.
- Earn Your Happy Ending: Gets promoted back to detective at the end of the final episode.
- Fair Cop: She's played by Drea de Matteo.
- Green-Eyed Monster: Tess doesn't like the idea that someone wants to have an affair with her husband.
- Murder the Hypotenuse: And nearly kills the woman in a bar if it wasn't for Espada's intervention.
- Played by: Hampton Fluker
A veteran police officer in the the 64th Precinct. Fancies himself as a Casanova Wannabe.
- Casanova Wannabe: This is according to the character profile released by NBC.
- Dirty Cop: One of the male officers known to Wozniak.
- Earn Your Happy Ending: Gets promoted back to detective along with Tess at the end of the final episode.
- Russian Roulette: Instigates one to Loman in order to intimidate him by giving him a seemingly unloaded revolver. It didn't work since Loman refused to use it.
- Those Two Guys: Is seen together always with Saperstein.
- Played by: Vincent Laresca
A veteran police officer in the the 64th Precinct.
- Dirty Cop: Another one in the 64th.
- Played by: Santino Fontana
A veteran police officer in the the 64th Precinct.
- Played by: Dayo Okeniyi
A new police officer in the the 64th Precinct. He has second thoughts about coming clean when he shot an unarmed drug dealer by accident.
- Break the Cutie: The others decide that he needs to be taken care of 'cause he's having second thoughts of covering an accidental death of an unarmed drug dealer.
- Broken Pedestal: Once Loman saw Harlee and the others intercept the armored truck.
- Heroic BSoD/My God, What Have I Done?: Loman goes into this after he realizes that the drug dealer he shot by mistake was just playing a videogame.
- New Meat: In the 64th. He partners with Santos on his first day.
- Protagonist Journey to Villain: By the end of the show, Michael slowly becomes a Dirty Cop.
- Token Good Teammate: One of the few in the 64th to not be involved in the Dirty Cop lifestyle. This annoys the others that they decide that he's a liability. Averted later on when he slowly adopts dirty tactics to keep New York safe.
- Played by: Gino Anthony Pesi
- Adorkable: A bit shy with Harlee. He's known to watch old classic movies.
- Hello, Attorney!: The male version of this in the show. He's handsome and Harlee is smitten by him in no time.
- Killed Off for Real: At the end of the first episode of the third season he is gunned down by another group of dirty cops.
- Played by: Michael Esper
A co-conspirator of Wozniak's criminal ops. He happens to be his gay lover and an officer in the NYPD Internal Affairs department.
- Asshole Victim: No one would miss him if he gets killed.Loman: He was a bad cop who did bad things and something bad happened to him. Amen.Wozniak: Amen.
- Dirty Cop: He's one with Wozniak.
- Killed Off for Real: Shot and killed by Loman when Pomp tried to shoot him with Wozniak's old Marine Corp sidearm.
- Mole in Charge: In charge of the NYPD IA Department.
- Played by: Dov Davidoff
An internal affairs officer stationed at the 64th.
- Played by: Bruce McGill
An NYPD officer in charge of the precient's intelligence unit. He's secretly in league with gangs.
- Big Bad: Of the third (final) season.
- Dirty Cop: Doesn't hesitate to use his status to cement his underworld partnership nor kill off any IU officers who are about to squeal on him or who don't go corrupt.
- Hero Killer: Masterminded the death of James Nava.
- Karmic Death: Just as he's about to be transferred to prison, Wozniak appears on the bus and strangles him to death.
- Boom, Headshot!: Cole shoots him in the head when he manages to convince Ramsey that he isn't the mole.
- Dirty Cop: Along with Ramsey and the intelligence unit.
- Hero Killer: He fired the bullets that killed James Nava.
- Speak Ill of the Dead: Matt and Harlee were about to decide he's not worth it and walk away. Until Bennett says that Nava cried like a baby before he died. Leading to Harlee and Matt changing their minds and arresting him, and earning him a punch in the face from Matt.
- Undying Loyalty: Refuses to give up anything incriminating against the intelligence.
- Played by: Nich Wechsler
A NYPD officer stationed with the IU, he's Harlee's secret ally to look for answers to why his unit went rogue.
- Played by: Warren Kole
The FBI agent in charge of running the sting op against Lt. Wozniak and other corrupt officers in the NYPD's 64th Precinct.
- Ax-Crazy: Becomes increasingly unhinged after being removed from the FBI. To the point of stalking Cristina and kidnapping Harlee. His sanity continues to slip away as time goes on.
- Blackmail: He uses it to get Harlee's cooperation when he implies that he can get her arrested for being a corrupt cop.
- Bad Guy Wins: While being dead, he proved to be right about never being free unless you face your transgressions to Harlee, hence why she turns herself in and goes to prison at the end of the show.
- Enemy Mine: Harlee asks him to help get Cristina out of the park she's in when Bianchi's hitman stalks her.
- Frame-Up: Kills Gina (The woman he hired to pose as Harlee.) and plants the bloody knife in her car.
- He Who Fights Monsters: Executes Linklater for killing his partner, as well skirting through FBI regulations just to bag his man.
- JerkAss: Casually says that Anna Kate's suicide points to Matt's characteristic as a father. Harlee couldn't believe he said that.
- Jerk Ass Has A Point: Before he was killed by Harlee, he did clarify that Harlee will never be healed unless she faces her transgressions, something she quotes at the end of the series in her letter to Cristina when she's sent to prison.
- Killed Off for Real: Harlee finally kills him when he breaks into her home.
- The Spymaster: He's running the sting op and he uses informants/electronic eavesdropping to get the dirt on the 64th Precinct.
- The Determinator: Still stalking Harlee after the kidnapping, he refuses to just give up on it.
- Murder-Suicide: Stahl planned to kill Harlee and himself since nothing else he tried worked, thankfully Harlee foiled that plan.
- Villainous Rescue: When a hitman sent by a cartel leader is about to assassinate Harlee, Stahl of all people sneaks up and kills the hitman.
- What the Hell, Hero?: Is berated for "arresting" Harlee, knowing that he'll be forced to take responsibility if the NYPD ever learns of a sting op made against them.Stahl: Detective Santos was having second thoughts, and that's to be expected. We work through them.Gail: By ordering an agent to pull a gun on her?
- Molly berated him for ordering her to threaten Harlee with her sidearm.
- Gail warns him that he needs to resign after Harlee shows proof that he's threatening her by investigating Miguel's ''disappearance'' by masquerading as a PI.
- Wild Card: In the third (final) season where his presence along hinders Ramsey's unit or Wozniak's.
- Played by: Annie Chang
A new recruit straight of the FBI Academy in Quantico, she's assigned to help Stahl run the sting op.
- But Not Too Foreign: She's Chinese-American.
- The Comically Serious: Molly's not above making a funny line. For instance, she asks Stahl if he has OCD for having a neat apartment.
- Mr. Exposition: Molly gives background information to Stahl (and to the audience) with whatever she can find regarding those involved in the Dirty Cop probe.
- New Meat: Recruited into the task force straight after graduating from Quantico.
- Nice Job Breaking It, Hero!: Stahl calls Molly out for releasing Miguel Zepeda earlier than expected in "What Devil Do".
- Number Two: To Stahl in the task force.
- Whatever Happenedto The Mouse: Is not seen in season 3.
- Weapon of Choice: Uses a Glock 26 as her sidearm.
- Played by: Leslie Silva
The director of the FBI's New York branch and the one responsible for managing Stahl's sting op.
- Played by: Sarah Jeffery
Harlee's only child, currently in high school. She's a known musical prodigy.
- Morality Pet: Her presence helped Harlee get them away from her abusive boyfriend. And is used by Stahl to get Harlee to cooperate or risk arrest.
- Played by: Lolita Davidovich
- Dark and Troubled Past: She lost her daughter to suicide after being depressed for some time. Unlike Matt, she was able to move on.
- Played by: Karsen Liotta
Matt and Linda's daughter, who died from suicide. Has appeared as a hallucination to Matt. (Played by Ray Liotta's real life daughter, Karsen.
- Driven to Suicide: According to Matt, what drove her to suicide (Overdose from taking 9 pills) was after they had a fight where Matt had meant to say she was wasting her potential, but said she was wasting space.
- Hallucinations: Has appeared to Matt as a hallucination a few times in the third season.
- Posthumous Character: She died right before the show started.
Matt and Linda's son, and the brother of Anna Kate.
- Roaring Rampage of Revenge: He beat up the drug dealer who sold Anna Kate the drugs she overdosed on and left him for dead, would have ended up in jail had Julia Ayres not covered it up.
Former police captain of Wozniak's precinct, and a corrupt council woman running for mayor.
- Played by: Otto Sanchez
- Played by: Ritchie Coster
- Asshole Victim: After he gets pushed by James, he breaks his neck. Then Harlee smothers him to death to help cover James' tracks and make it look like self-defence.
- Bad Boss: He executes one of his soldiers with a shot to the head, due to not doing his job.
- Big Bad: Of season 2.
- Would Hit a Girl: He has no problems threatening to hurt Harlee, in part for framing him.
- Would Hurt a Child: He has a hitman try to kill Cristina.
- Played by: Stephen Lang
- Boom, Headshot!: When Harlee and Matt try to hand him over to Stahl and the FBI, Stahl refuses their offer and shoots him in the head and orders them to stick to the assignment of getting Julia Ayres
- Mastermind: Behind the armored car heist.