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 Courteney Cox Dr. Maddox Guest Star Sam Lloyd Ted Guest Star Travis Schuldt Keith Guest Star Eliza Coupe Denise Guest Star Betsy Beutler Katie Guest Star Aziz Ansari Ed Guest Star James Ritz Mr. Hicks Guest Star Eric Artell Rodney Guest Star Taran Killam Jimmy Guest Star Aseem Batra Josephine Guest Star Michael Alan Spiller The Balloon Guy Guest Star, Director Jack Grinnage Marvell Guest Star Bill Lawrence Executive Producer Angela Nissel Writer