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
Bizarre ER returned after for five more episodes. "Bizarre ER" returned for a twelve-part third series from 10 May 2010 and finished on 19 July 2010. The series was filmed at the Northampton General Hospital. The series returned for a ten-part fourth series on 28 March 2011, now narrated by Sheridan Smith. Filming takes place at Northampton General Hospital as well as Bradford Royal Infirmary. The series also features bizarre operations that have happened around the world. Series 5 is set in the USA with John Barrowman as narrator, it started in March 2013 and ended in May 2013. Series 6 is