- Detective Sergeant Barney Miller (played by Hal Linden): The sarcastic and level-headed head of the 12th Precinct in Greenwich Village, New York City.
- Detective Fish (played by Abe Vigoda): A world-weary and pessimistic veteran detective known for his dry wit and cynical outlook on life.
- Detective Ron Harris (played by Ron Glass): A young, African-American detective who is idealistic and eager to prove himself.
- Detective Wojciehowicz (played by Max Gail): A streetwise and often comical detective of Polish descent known for his love of puns and malapropisms.
- Officer Nick Yemana (played by Jack Soo): A friendly and compassionate Japanese-American officer who serves as the desk sergeant.
- Sergeant Dietrich (played by Steve Landesberg): A bumbling and insecure superior officer who often creates more problems than he solves.
- Lieutenant Scanlon (played by George Murdock): The strict and no-nonsense commander of the 12th Precinct who occasionally clashes with Miller.
- Officer Carl Levitt (played by Ron Carey): A young and eager officer who joins the precinct in later seasons.
These characters make up the ensemble cast of "Barney Miller", with their interactions and dynamics driving the comedic situations and storylines of the show.