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 (TV series) theme returned) and songs used on the series. In March 2012, Warner Bros. International Television announced that they would sell the format rights to "ER" to overseas territories. This allowed foreign countries to produce their own version of the series. In June 2013, Warner Bros. International Television and Emotion Production from Belgrade, Serbia, announced a Serbian version of "ER." "Urgentni Centar" premiered on October 6, 2014 on TV Prva. A Colombian version is also in the works. ER (TV series) ER is an American medical drama television series created by novelist and medical doctor Michael Crichton that aired on NBC