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 Johnny Kastl Doug Guest Star Robert Maschio Todd Guest Star Lauren Stamile Shannon Guest Star Susan Blakeslee Gayle Guest Star Harry Danner Mr. Clark Guest Star Kit Pongetti Lady Guest Star Shawn Card Intern Guest Star Amy Aitken Nurse's Aid Guest Star Anthony Fitzgerald Flashback Nerd Guest Star Bill Lawrence Executive Producer Will Mackenzie Director Janae Bakken Writer