24 of 25:
George Clooney had his breakout role as Dr. Ross in the hospital drama 'ER.'
The drama became America's top rated show, earning Clooney Emmy nominations in 1995 and 1996 for Outstanding Lead Actor.
'I can be a schmuck all day long, at the end of it save some old lady's life and still be a hero. If you stuck a mannequin in my part, he'd get all the fan mail, Clooney told People magazine.
Pictured: Clooney appears in a scene from the long-running hospital drama 'ER.'
( Photo / Constant c Productions / John Wells Productions / Amblin Entertainment)