[citation needed] He considered following in his parents' footsteps, but ultimately decided that he "would rather sing about love than preach it.

In 1964 he appeared in the Hallmark Hall of Fame presentation of The Fantastiks with Ricardo Montalbán and Susan Watson.

[5] In 1967 Davidson made his film debut in The Happiest Millionaire, alongside Lesley Ann Warren and Fred MacMurray.

Davidson made numerous appearances on the original Hollywood Squares, from the game show's premiere in 1966 to its cancellation in 1981.

He was known for his long-winded bluffs which often fooled contestants with his often ridiculous answers to questions the program's host, Peter Marshall, posed.

Most times, Marshall could barely conceal a grin as Davidson began some far-fetched but plausible explanations for his answers, often prefaced with some misleading statement like "I just read about it in the New England Journal of Medicine, it was a fascinating study, and it said that..." Davidson put over these preposterous stories with such sincerity that many a contestant was fooled more than once.

In 1974 he guest-starred on the television series The Streets of San Francisco, in the episode "Mask of Death", portraying a cross-dressing lounge singer who murders his/her fans.

In the late 1970s, the actor appeared 87 times as a regular guest host on The Tonight Show Starring Johnny Carson.

[5] Davidson appeared as a host on real estate promoter Dave Del Dotto’s paid programs during the late 1980s and early 1990s, which were notable for taking place in outdoor, scenic settings (such as Hawaii).

These "infomercials", as they have come to be called, often appeared on late night television and were a staple for years on many cable channels till the FCC filed a complaint against Del Dotto in 1995, alleging that he had "made false and unsubstantiated representations" in his programs.

[citation needed] Following his run on Hollywood Squares, he was one of six people who auditioned to host the CBS daytime version of Wheel of Fortune (in the end, Bob Goen was hired).

[17] Davidson acted in many movies, including The Happiest Millionaire (1967), The One and Only, Genuine, Original Family Band (1968), Coffee, Tea or Me?

Davidson has appeared in productions of A Funny Thing Happened on the Way to the Forum, Kismet, State Fair, Man of La Mancha, Chicago, and The Will Rogers Follies, at the Surflight Theatre in Long Beach Island, New Jersey.

[21] In 2016, Davidson played Norman Thayer in On Golden Pond at Judson Theatre Company in Pinehurst, North Carolina.