Anthony Edwards Dr. Mark Greene Actor George Clooney Dr. Doug Ross Actor Sherry Stringfield Dr. Susan Lewis Actor Eriq La Salle Dr. Peter Benton Actor Noah Wyle Dr. John Carter Actor Julianna Margulies Head Nurse Carol Hathaway Actor Gloria Reuben Jeanie Boulet Actor Red Buttons Jules 'Ruby' Rubadoux Guest Star Brandon Maggart Stan Calaus Guest Star Joan Copeland Hanna Steiner Guest Star Ron Rifkin Guest Star Tony Plana Priest Guest Star Sean Murray Bret Maddocks Guest Star Danny Goldring Tony Maddocks Guest Star Laura Innes Dr. Kerry Weaver Guest Star Jacob Vargas Diablo Guest Star Bradley Whitford Sean O'Brien Guest Star Ellen Crawford Nurse Lydia Wright Guest Star Yvette Freeman Nurse Haleh Adams Guest Star Michael Crichton Executive Producer John Wells Executive Producer