Anthony Edwards Dr. Mark Greene Actor George Clooney Dr. Doug Ross 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 Laura Innes Dr. Kerry Weaver Actor Harry Lennix Dr. Greg Fischer Guest Star Michael Beach Guest Star Lisa Nicole Carson Guest Star Amy Aquino Dr. Janet Coburn Guest Star Michael Tomlinson Dr. Keith Fecteau Guest Star Stanley Kamel Dr. Fin Loesch Guest Star Susan Krebs Transplant Surgical Nurse Guest Star Joe Lisi Mr. Gunther Guest Star Spider Madison Crazy Guy Guest Star Heather Matarazzo Alyssa Gunther Guest Star Michael Crichton Executive Producer John Wells Executive Producer