"Captain Kangaroo" ran weekday mornings on the CBS network from 1955 to 1985, featuring the grandfatherly Keeshan, his friend "Mr. Greenjeans," and puppets including "Bunny Rabbit" and "Mr. Moose."
The program was an innovative contrast to television's standard cartoon fare.
Wearing a Dutch-boy haircut, big-pocket uniform and cap, Keeshan, a former U.S. Marine, would talk directly into the camera to an audience of millions of young viewers.
He called them "my yupperoos" and featured shows on music, science and literature.
Keenshan originated the educational approach for the early morning children's program in New York, where he played an Alpine toymaker on "Tinkers Workshop" at WABC-TV.
He was working as an intern-producer when he created the horn-honking character Clarabell the Clown on the "Howdy Doody Show. He left in 1952 and became Corny, another clown, on "Time for Fun."
He died in Vermont after a long illness.