According to the NYT, Mr. Morgan had continuing roles in at least 10 TV series, and once estimated that he had appeared in one prime-time show or another for 35 straight years; and he had over 100 movie roles. He was never a star -- he was something more important and challenging, an actor.
It was his role as M*A*S*H's Colonel Potter, from 1975 to 1983, that most people will remember him for. M*A*S*H was one of the shows I grew up on, and certainly had an influence on me. Rest in peace, Mr. Morgan.