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 Adam Goldberg Joshua Shem, `Mr. Sullivan' Guest Star Ellen Crawford Nurse Lydia Wright Guest Star Yvette Freeman Nurse Haleh Adams Guest Star Bruce Nozick Craig Simon Guest Star Barbara Tyson Gwen Guest Star Ron Rifkin Guest Star Ron Eldard Guest Star Christine Elise Guest Star Christine Harnos Guest Star William H. Macy Dr. David Morgenstern Guest Star Piper Laurie Sarah Ross Guest Star Michael Crichton Executive Producer John Wells Executive Producer