- Rusty Beck (Graham Patrick Martin): Sharon Raydor's adoptive son, a former prostitute who witnessed Phillip Stroh burying a body. He has since started an investigative video blog called Identity and has started preparing for law school after finishing his journalism degree.
- Assistant Chief Russell Taylor (Robert Gossett): Director of Operations until Season 5 episode "White Lies, Part 1". He was then-Captain Raydor's first immediate supervisor when she assumed command of MCD. The former commanding officer of the Robbery-Homicide Division and later press liaison for the Major Crimes Division, Taylor long felt passed over and unappreciated.
- Assistant Chief Leo Mason (Leonard Roberts): Director of Operations from Season 5 finale "Shockwave, Part 2" onward. He is Commander Raydor's immediate supervisor. Mason was previously the Commander of the Criminal Intelligence Division.
- Deputy Chief Fritz Howard (Jon Tenney): Commanding officer of the Special Operations Bureau during Major Crimes (Season 3 onward). During The Closer and the first two seasons of Major Crimes, he was a Special Agent for the F.B.I. and the liaison officer to the LAPD.
- Commander Sharon Raydor (Mary McDonnell): The commanding officer of the Major Crimes Division. She recently received a promotion from Captain to Commander.
- Lieutenant Louie Provenza (GW Bailey): The division's senior member and Sharon's second-in-command. He is the immediate supervisor of the team in the field.
- Lieutenant Andy Flynn (Anthony Denison): Provenza's partner.
- Lieutenant Michael Tao (Michael Paul Chan): The squad's forensics and technology expert; Tao previously was assigned to the LAPD's Scientific Investigation Division (SID).
- Detective Julio Sanchez (Raymond Cruz): The squad's gang and weapons expert, experience gained from his days on the LAPD's gang intelligence unit.
- Detective Amy Sykes (Kearran Giovanni): Transferred to the division from the Special Investigation Section, she is an expert on undercover operations. Sykes is a military veteran who served in Afghanistan.
- Detective Wes Nolan (Daniel DiTomasso): Transferred to the division from the Special Investigation Section after spending nearly six years undercover in a white supremacist gang. (Season 5, "White Lies, Part 3" onward).
- Civilian Surveillance Coordinator Buzz Watson (Phillip P. Keene): Buzz is the Scientific Investigation Division's civilian investigator assigned to the division. He is responsible for memorializing crime scenes, and managing technology in the field and in the squad's office. He also recently qualified as a LAPD reserve police officer.
- Dr. Fernando Morales (Jonathan Del Arco): A Los Angeles County Deputy Medical Examiner who coordinates with the team, conducting autopsies. Morales has a sharp medical mind and and equally sharp, sometimes sarcastic, wit. Morales is gay, and provides expertise on the gay community in Los Angeles.
- Investigator Kendall (Ransford Doherty): Kendall is responsible for examining the body at the crime scene and taking initial measurements, as well as preparing the body for transportation to the Los Angeles County Coroner's office.
- Deputy District Attorney Andrea Hobbs (Kathe Mazur): The DDA who works most frequently with Major Crimes, Hobbs is a team player.
- Deputy District Attorney Emma Rios (Nadine Velazquez): A new, inexperienced DDA under Hobbs' supervision, she is charged with preparing the case against Phillip Stroh (Season 2).
Recurring characters Edit
- Lieutenant Chuck Cooper (Malcolm-Jamal Warner): Lieutenant Cooper is the commanding officer of the Special Investigation Section (SIS) of the LAPD.
- Detective Robert Oderno (Brandon Barash): Robert Oderno is a detective in the LAPD's Missing Persons Unit.
- Gustavo Wallace (Rene Rosado): Gus Wallace is the older brother of murder victim Mariana Wallace. He is currently dating Rusty Beck.
- Deputy Chief Winnie Davis (Camryn Manheim): Chief Davis is the LAPD's Assistant Director of Operations.