Zach Braff Dr. John "J.D." Dorian Actor Sarah Chalke Dr. Elliott Reid Actor Donald Faison Dr. Chris Turk Actor John C. McGinley Dr. Perry Cox Actor Judy Reyes Nurse Carla Espinosa Actor Ken Jenkins Dr. Bob Kelso Actor Neil Flynn The Janitor Actor Julianna Margulies Neena Guest Star Richard Kind Mr. Korman Guest Star Sam Lloyd Ted Guest Star Robert Maschio Todd Guest Star Christa Miller Jordan Guest Star Jon Polito Mr. Summers Guest Star Tara Callaghan Mother Guest Star Dutch Hofstetter Young Dr. Cox Guest Star Zach Mills Young J.D. Guest Star Alysia Joy Powell Karen Guest Star Stevie Walsh Jr. Young Turk Guest Star Bill Lawrence Executive Producer Chris Koch Director Debra Fordham Writer