Donald Faison
John C. McGinley
Ken Jenkins
Zach Braff
Sarah Chalke
Neil Flynn
Judy Reyes
Robert Maschio
Sam Lloyd
Aloma Wright

Donald Faison as Dr. Christopher Turk (182 episodes, 2001-2010)
John C. McGinley as Dr. Perry Cox (182 episodes, 2001-2010)
Ken Jenkins as Dr. Bob Kelso (178 episodes, 2001-2010)
Zach Braff as Dr. John 'J.D.' Dorian (175 episodes, 2001-2010)
Sarah Chalke as Dr. Elliot Reid (173 episodes, 2001-2010)
Neil Flynn as The Janitor (170 episodes, 2001-2009)
Judy Reyes as Nurse Carla Espinosa (169 episodes, 2001-2009)
Robert Maschio as Dr. Todd Quinlan (127 episodes, 2001-2010)
Sam Lloyd as Ted Buckland (95 episodes, 2001-2009)
Aloma Wright as Nurse Laverne Roberts / ... (92 episodes, 2001-2009)
Christa Miller as Jordan Sullivan (89 episodes, 2001-2010)
Johnny Kastl as Dr. Doug Murphy (48 episodes, 2001-2009)
Travis Schuldt as Keith (39 episodes, 2006-2009)
Eliza Coupe as Dr. Denise Mahoney (24 episodes, 2009-2010)
Charles Rahi Chun as Dr. Wen (21 episodes, 2001-2009)