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 Alex Kingston Dr. Elizabeth Corday Actor Maria Bello Dr. Anna Del Amico Actor Telma Hopkins Carlene Guest Star Brad William Henke John Guest Star Michael Ironside Dr. William 'Wild Willy' Swift Guest Star Paul McCrane Robert Romano Guest Star Dennis Boutsikaris Dr. David Kotlowitz Guest Star Sarah Hudnut Laura Brown Guest Star Trevor Morgan Scott Anspaugh Guest Star Erica Yohn Ann Reilly Guest Star Stacey Travis Det. Weller Guest Star Mariska Hargitay Guest Star Rose Gregorio Helen Hathaway Guest Star Michael Crichton Executive Producer John Wells Executive Producer