During World War II, DeRita joined the USO, performing throughout Britain, France, and the Pacific with such celebrities as Bing Crosby and Randolph Scott.

In the 1944 comedy film The Doughgirls, about the housing shortage in wartime Washington, D.C., he had an uncredited role as "the Stranger", a bewildered man who repeatedly showed up in scenes looking for a place to sleep.

[citation needed] In 1946, DeRita was hired by Columbia Pictures Short Subjects Division head/director Jules White to star in his own series of comedies.

Regarding his Columbia shorts series, DeRita said, "My comedy in those scripts was limited to getting hit on the head with something, then going over to my screen wife to say, 'Honey, don't leave me!'

[citation needed] When Shemp Howard died of a heart attack on November 22, 1955, the Three Stooges were still making short comedies for Columbia Pictures.

Columbia eventually shut down the short-subjects department at the end of 1957, and Besser quit the act in 1958 to take care of his ailing wife.

But Columbia began releasing their shorts to television through their Screen Gems subsidiary, and their popularity with children put them back on top.

[1] When he first joined the act, shortly after appearing in a dramatic role in the Gregory Peck Western, The Bravados, DeRita wore his hair in a style similar to that of former Stooge Shemp Howard and did so during initial live stage performances.

Moe and Larry's advanced age, as well as pressure from children's advocacy groups, resulted in milder forms of their trademark slapstick.

[citation needed] DeRita remained a member of the team through the 1960s, participating in a full workload of television appearances and commercials, a multiyear movie contract, and The New Three Stooges animated cartoons series, which included live-action introductions.

In January 1970 Larry Fine had a stroke during the production of Kook's Tour, a pilot for a planned TV series, which put all new Stooges-related material on hold.

He recruited burlesque and vaudeville veterans Mousie Garner and Frank Mitchell to replace Moe and Larry for nightclub engagements.