For his work on Mary Poppins, he shared Academy Award nominations for Best Picture with Walt Disney, and for Best Writing, Screenplay Based on Material from Another Medium with Don DaGradi.
In 1970 an article in Variety listed him as the second most successful film producer of all time in terms of money-earning movies even though he was "a guy no one's ever heard of".
He worked as a press agent for 15 years at the Ettinger Company and started writing jokes as a sideline on the suggestion of client Edgar Buchanan.
[4] He joined the Disney company in 1943 as a press agent and began writing the Mickey Mouse comic strip as a sideline.
"[3] Due to Walsh's lack of interest in Mickey as a character, and to his own taste for science fiction, mystery and horror, the stories he wrote for the strip quickly became very different from those of the previous decade.
Notably, Walsh created Eega Beeva, an evolved man from the future who became one the strip's protagonists from 1947 to 1950, effectively replacing Goofy as Mickey's sidekick.
Walsh produced a number of huge successes, including Davy Crockett (1954–55) and The Mickey Mouse Club (1955-59).
He also wrote the feature The Littlest Outlaw (1955) and produced a number of serials that aired as part of The Mickey Mouse Club, including Spin and Marty, Corky and White Shadow, The Hardy Boys: The Mystery of the Applegate Treasure, Adventure in Dairyland, The Adventures of Clint and Mac, and Walt Disney Presents: Annette.
[8] Walsh wrote and produced The Shaggy Dog (1959) with Fred MacMurray, Tommy Kirk and Kevin Corcoran.
Walsh wrote and produced a series of comedies starring MacMurray and Kirk, all very popular: The Absent-Minded Professor (1961), a fantasy; Bon Voyage!
Walsh died of a heart attack in Los Angeles in 1975,[4][13] and was interred in Glendale's Forest Lawn Memorial Park Cemetery.