In the early 1950s he adopted his stage name in remembrance of Beatrice MacLeod, his drama teacher at Ithaca. He chose the first name Gavin after a character in an episode of the anthology television series “Climax.”
After finding some stage work, Mr. MacLeod made his television debut as a guest star on “The Walter Winchell Files,” a crime drama. His first credited movie role was a small part as a police lieutenant in “I Want to Live!,” a 1958 drama with Susan Hayward as a woman facing the death penalty. In 1959 he appeared in the Korean War film “Pork Chop Hill” and Blake Edwards’s naval comedy “Operation Petticoat.”
By the 1960s Mr. MacLeod was appearing regularly on television series, with guest-starring roles on “Perry Mason,” “Combat!,” “Death Valley Days,” “Dr. Kildare,” “The Untouchables” and other shows. His part on “McHale’s Navy,” which starred Ernest Borgnine, was his first job as a series regular. His character, Seaman Joseph Haines, one of a crew of misfits aboard a World War II PT boat, was known as Happy. But Mr. MacLeod, feeling underused, was anything but.
“I had, like, two lines a week,” Mr. MacLeod said in a videotaped interview for the Archive of American Television. “I started feeling sorry for myself; I started drinking. I felt that as an actor I was just going down the tubes.”
As he told the story, one night he was driving, while drunk, on Mulholland Drive in the hills above Los Angeles when he impulsively decided to kill himself by driving off the road. But he stopped himself, jamming on the brakes at the last moment. Shaken, he recalled, he made his way to the nearby house of a friend, the actor Robert Blake, who persuaded him to see a psychiatrist.
He quit “McHale’s Navy” in 1964, after two seasons, and began finding more satisfying parts, including a supporting one in the 1966 film “The Sand Pebbles” with Steve McQueen.