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 Kathleen Wilhoite Actor Laura Innes Dr. Kerry Weaver Actor Joanna Gleason Iris Guest Star Marg Helgenberger Karen Hines Guest Star Jeff Daurey Virgil Guest Star Bibi Besch Ethel Garvey Guest Star Scott Michael Campbell Guest Star Matthew Glave Dr. Dale Edson Guest Star Michael C. Mahon Joe, Chloe's Boyfriend Guest Star Yvette Freeman Nurse Haleh Adams Guest Star Claudette Nevins Judge Guest Star Christine Elise Guest Star Michael Crichton Executive Producer John Wells Executive Producer