Oliver Davis

ER is an American medical drama television series created by Michael Crichton that aired on NBC from September 19, 1994, to April 2, 2009. It was produced by Constant c Productions and Amblin Television, in association with Warner Bros. Television. The series follows the inner life of the emergency room (ER) of fictional Cook County General Hospital in Chicago, and various critical issues faced by the room's physicians and staff.

ER 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.