What type of doctor was played by George Clooney in the TV medical drama series "ER"?

Douglas Ross, M.D. (Doctor of Medicine) is a fictional character from the National Broadcasting Company (NBC) medical drama series "ER", portrayed by American actor George Clooney. He is a paediatrician (a doctor who studies and treats the diseases of children), employed by the pediatric service, but works in the "ER". He appears from the pilot episode before departing in the fifth season episode "The Storm - Part II". Clooney later made guest appearances in the sixth season episode "Such Sweet Sorrow" and in the fifteenth season episode "Old Times".

"ER" is an American medical drama television series created by Michael Crichton that aired from September 19, 1994, to April 2, 2009, with a total of 331 episodes spanning 15 seasons. It was produced by Constant C Productions and Amblin Television, in association with Warner Bros. Television. "ER" follows the inner life of the emergency room (ER) of Cook County General Hospital (a fictionalized version of the real Cook County Hospital) in Chicago, and various critical issues faced by the department's physicians and staff.