Andy Samberg as Detective Jake Peralta, a talented but childish detective. It is revealed that his father abandoned him and his mother when he was very young. Peralta shows "class clown" traits, constantly pulling pranks and making jokes at the expense of his colleagues, particularly his partner Santiago; this is later revealed to be secret romantic feelings for her. Peralta's frequent disregard for decorum and protocol regularly puts him at odds with the by-the-book Captain Holt, though the two quickly develop a mutual professional respect for each other.
Andre Braugher as Captain Ray Holt, the 99th Precinct's strict new Commanding Officer. Holt is known for his cold and robotic manner of speaking and lack of outwardly visible emotion. The Nine-Nine is Holt's first command despite many years of outstanding service, something he attributes to prejudice against him being gay. He is married to a university professor named Kevin.
Stephanie Beatriz as Detective Rosa Diaz, a smart, tough, and mysterious detective. She attended parochial school and later studied ballet, and went to the police academy with Jake. She has anger management issues, which leads to most of the precinct being scared of her.
Terry Crews as Detective Sergeant Terence "Terry" Jeffords, the detective squad's leader. He previously worked with Holt at another precinct where he was overweight and was given the nickname "Terry Titties". A year prior to the show's beginning, following the birth of twin baby girls named Cagney and Lacey, he suffered a breakdown of sorts where he "lost his edge" and any desire to work in the field due to a fear of losing his life and leaving his children without a father. He has since cautiously returned to working in the field.
Melissa Fumero as Detective Amy Santiago, Jake's uptight and overachieving Cuban-American partner. She is continually trying to ingratiate herself with Captain Holt. She has a competitive nature stemming from having seven brothers.
Joe Lo Truglio as Detective Charles Boyle, a nervous, clumsy but honest and hard-working detective who has a crush on Detective Diaz. He is divorced from his wife, who had numerous affairs during their marriage. He is also a huge, unapologetic foodie.
Chelsea Peretti as Administrator Gina Linetti, the 99th Precinct's sardonic civilian administrator. She belongs to a dance troupe called "Floorgasm." She has displayed a penchant for kleptomania and extreme narcissism, but is generally regarded as harmless if annoying by the rest of the staff.
Dirk Blocker as Detective Michael Hitchcock. He usually seems to have no idea what's going on, even if he doesn't let that dampen his enthusiasm. He is prone to taking his shirt off at inappropriate times. He went bald at 15.
Joel McKinnon Miller as Detective Norm Scully. He is middle-aged, lazy and overweight. Scully is a proficient opera singer. He used to date Hitchcock's wife.
Mlepnos (Spelled M-L-E-P-Clay) (Fred Armisen), a confused foreign man living in a building where a murder took place. The detectives run into Mlepnos while searching for witnesses, showing him a photo of the victim, which he keeps. He shows up again in "Operation: Broken Feather."
Fire Marshal Boone (Patton Oswalt), the dimwitted fire marshal of the local fire station precinct. He hates the detectives of 99 intensely, but reaches an understanding with Jake when they discover that they both were abandoned at a young age by their fathers.
Vivian Ludley (Marilu Henner), a food author who becomes romantically involved with Boyle. In "Full Boyle", she and Boyle become engaged.
Detective Warren Pembroke (Dean Winters), a detective for the Major Crimes Unit notorious for taking over cases that are mostly solved and getting all of the credit for solving them, which earns him the nickname "The Vulture."
Doorman (Andy Richter), a rude doorman who refuses to assist Jake during a routine questioning.
Jimmy Brogan (Stacy Keach), a crime writer from the 1970s whom Jake greatly admires. Brogan is revealed to be homophobic, vengeful, and manipulative, disillusioning Jake and leading to a physical altercation between the two.
Dustin Whitman (Kid Cudi), a perpetrator Jake arrests on suspicion of burglary. Mocks Jake by calling him "Joke Peralta."
Doug Judy (Craig Robinson) a.k.a. 'The Pontiac Bandit,' a thief and forger who escapes from Peralta and Diaz by pretending to have information on a different man who Peralta believed to be the actual 'Pontiac bandit'.
Kevin Cozner (Marc Evan Jackson), Holt's husband who dislikes the NYPD due to their treatment of Holt and his homosexuality during his earlier years on the force. He claims Holt is the 'funny' one in their relationship.
Brooklyn Nine-Nine has received positive reviews from critics. As of January 2014[update], Rotten Tomatoes gives it a score of 88% based on 49 reviews, with the consensus "Led by the surprisingly effective pairing of Andy Samberg and Andre Braugher, Brooklyn Nine-Nine is a charming, intelligently written take on the cop show format."Metacritic gives the show a weighted average rating of 70/100, based on 33 reviews, indicating "Generally favorable reviews".