Cast of ER Cast of ER "ER" is an American drama series that aired on NBC from September 19, 1994 until April 2, 2009. The series featured a large ensemble cast that changed dramatically over its long run. The main cast was augmented by a wealth of recurring characters and award-winning guest stars. The original starring cast consisted of Anthony Edwards as Dr. Mark Greene, George Clooney as Dr. Douglas "Doug" Ross, Sherry Stringfield as Dr. Susan Lewis, Noah Wyle as medical student (later Dr.) John Carter, and Eriq La Salle as Dr. Peter Benton. Julianna Margulies guest starred in the pilot as
ER (season 1) a number of nominations for other awards which are listed in the List of ER awards and nominations. ER (season 1) The first season of the American fictional drama television series "ER" aired from 1994–1995 with 25 episodes. The 2-hour pilot episode aired on September 19, 1994 and was followed by 24 other episodes, including the season finale that aired on May 18, 1995. In "ER"'s first season, the core cast consisted of Chief Resident Dr. Mark Greene, pediatric resident Dr. Doug Ross, second-year resident Dr. Susan Lewis, medical student John Carter, head nurse Carol Hathaway, and second-year surgical resident