Dr. John 'J.D.' Dorian (166 episodes, 2001-2009)
Dr. Elliot Reid (166 episodes, 2001-2009)
Dr. Christopher Turk (166 episodes, 2001-2009)
The Janitor (166 episodes, 2001-2009)
Dr. Bob Kelso (166 episodes, 2001-2009)
Dr. Perry Cox (166 episodes, 2001-2009)
Nurse Carla Espinosa (166 episodes, 2001-2009)
Ted Buckland (91 episodes, 2001-2009)
Jordan Sullivan (86 episodes, 2001-2009)
Dr. Doug Murphy (49 episodes, 2001-2009)
Keith (38 episodes, 2006-2009)
Dr. Mickhead (21 episodes, 2003-2009)
Dr. Wen (20 episodes, 2001-2006)
Baby Jack (14 episodes, 2006-2009)
Crispin (14 episodes, 2002-2009)
Randall (13 episodes, 2002-2009)
Roy (12 episodes, 2002-2009)
Danni Sullivan (11 episodes, 2003-2005)
Gloria (10 episodes, 2006-2007)
Lisa (10 episodes, 2006-2007)
Rex (9 episodes, 2006-2007)
Dr. Molly Clock (9 episodes, 2004-2005)
Randall Winston (9 episodes, 2004-2009)
Denise (8 episodes, 2009)
Jason 'Cabbage' Cabbagio (8 episodes, 2006-2007)
Dr. Beardface (7 episodes, 2004-2009)
Mrs. Wilk (7 episodes, 2006)
Troy (7 episodes, 2002-2006)
Dr. Zeltzer (6 episodes, 2002-2009)
Dr. Matthews (6 episodes, 2006-2007)
Colonel Doctor (6 episodes, 2006-2009)
Young J.D. (6 episodes, 2001-2005)
Boon (6 episodes, 2007-2009)
Dan Dorian (6 episodes, 2002-2007)
Jill Tracy (5 episodes, 2001-2007)
Franklyn (5 episodes, 2002-2004)
Dr. Miller (5 episodes, 2004)
Nurse Paul Flowers (4 episodes, 2003)
Hooch (4 episodes, 2005-2007)
Private Brian Dancer (4 episodes, 2007)
Josephine (4 episodes, 2007-2009)
Dr. Johnson (4 episodes, 2005-2006)
Kathy (4 episodes, 2005-2006)
Dr. Jeffrey Steadman (4 episodes, 2001-2003)
Jake (4 episodes, 2005-2006)
Debbie (4 episodes, 2007-2008)
Nurse Lauren Halston (4 episodes, 2002-2005)
Harvey Corman (4 episodes, 2003-2004)
Chet (4 episodes, 2003-2004)
Jamie Moyer (3 episodes, 2003)
Dr. Taylor Maddox (3 episodes, 2009)
Lisa the Gift Shop Girl (3 episodes, 2002-2006)
Bonnie (3 episodes, 2001-2002)
Dr. Ginny Gerson (3 episodes, 2002-2003)
Dr. Simotas (3 episodes, 2001-2002)
Ben Sullivan (3 episodes, 2002-2004)
Sam Thompson (3 episodes, 2004-2007)
Lily Reid (3 episodes, 2002-2006)
Nurse Tisdale (3 episodes, 2001-2005)
Mark Espinosa (3 episodes, 2003-2004)
Nurse (3 episodes, 2003-2004)
Simon Reid (2 episodes, 2002)
Julie Keaton (2 episodes, 2002)
Julie Quinn (2 episodes, 2006)
Melody O'Harra (2 episodes, 2007)
Dr. Hendrick (2 episodes, 2006-2007)
Mr. Hoffner (2 episodes, 2002-2005)
Stephanie Gooch (2 episodes, 2009)
Himself (2 episodes, 2001-2002)
Kristen Murphy (2 episodes, 2002)
Nurse Martinez (2 episodes, 2006)
Robyn (2 episodes, 2007-2009)
Old Man (2 episodes, 2006)
Dr. Donna (2 episodes, 2003-2007)
Marvell (2 episodes, 2009)
Ralphie (2 episodes, 2003)
Lester Roberts (2 episodes, 2007)
Fellowship Director (2 episodes, 2006)
Mrs. Tanner (2 episodes, 2001-2004)
Dr. Green (2 episodes, 2004-2007)
Neena Broderick (2 episodes, 2004)
Sam Dorian (2 episodes, 2002)
Margaret Turk (2 episodes, 2002-2004)
Elaine (2 episodes, 2003-2004)
Dr. Walch (2 episodes, 2002-2004)
Mr. Summers (2 episodes, 2004)
Young Elliot (2 episodes, 2002-2003)
Mother (2 episodes, 2004)
Dr. Akbar (2 episodes, 2004)
Mr. Bober (2 episodes, 2002-2003)
Young Dr.Cox (2 episodes, 2004)
Board Member (2 episodes, 2003-2007)
Priest (2 episodes, 2003-2006)
Dr. Kim (2 episodes, 2004-2006)
Young Turk (2 episodes, 2004)
Orderly #3 (2 episodes, 2002-2004)
Nurse (2 episodes, 2002-2003)
Young Janitor (2 episodes, 2004-2005)
Dr. Kevin Casey (2 episodes, 2004)
Janice (2 episodes, 2004)
