[5] An urban legend claims that actor Lee Marvin said on The Tonight Show that he had fought alongside Keeshan at the Battle of Iwo Jima in 1945.

[6][7] Other legends had compounded on it, such that Keeshan was a trained killer,[8] that he was awarded the Navy Cross,[9][10] that he was a tough sergeant who saved the lives of dozens of men and women in the war,[11] and that he destroyed a German tank in action in North Africa (an apparent confusion with a similarly named British soldier).

[17] By September 21, 1953, Keeshan came back to local TV on WABC-TV, Channel 7 in New York City, in a new children's show, Time for Fun.

[19] Developing ideas from Tinker's Workshop, Keeshan and his long-time friend Jack Miller submitted the concept of Captain Kangaroo to the CBS network, which was looking for innovative approaches to children's television programming.

The New York Times commented: "Captain Kangaroo, a round-faced, pleasant, mustachioed man possessed of an unshakable calm ... was one of the most enduring characters television ever produced.

Keeshan, in his role as the central characters in both Captain Kangaroo and Mister Mayor, heavily promoted the products of the Schwinn Bicycle Co., a sponsor, directly on-air to his audience.

[21] Keeshan suffered a severe heart attack just moments after stepping off a plane at Toronto Pearson International Airport on July 11, 1981, which pushed the start of a revamped version of his show back to at least mid-August.

[26] Despite these accolades, Keeshan's show was shortened from its hour-long format to 30 minutes in 1981, to make room for the expansion of the CBS Morning News lineup.

After Captain Kangaroo ended, Keeshan hosted 1985's CBS Storybreak, which featured animated versions of children's literature.

[27] In 1987, he founded Corporate Family Solutions with former Tennessee Republican governor Lamar Alexander, which provided day-care programs to businesses.

[32] In the 1990s, Keeshan expressed an interest in bringing back a new version of Captain Kangaroo as a gentler and kinder answer to the violent cartoons on children's television.

Despite having sponsors and television stations lined up, he was unable to obtain permission from ICM, the company that owned the rights to Captain Kangaroo at that time.

Keeshan resided on Melbury Road in Babylon Village, Long Island, New York, before moving to spend the last 14 years of his life in Norwich, Vermont, where he became a children's advocate, as well as an author.