[1][2] While in Manila, he was made assistant manager of the enlisted men's club at the Far East Air Force (FEAF) headquarters.

[1][2] After the war, he traveled to Hollywood in 1946 to pursue a career as an actor, he made his acting debut in the feature film, Stars Over Texas as Peddler Tucker.

[6] Smith's best-remembered on-screen character was Otis Campbell, the town drunk on The Andy Griffith Show, during most of the series' run from 1960 to 1967.

Smith, however, in a 1964 interview with his hometown paper, said he was a “social drinker.” The Otis character stopped appearing in the sitcom towards the end of the series because of sponsor concerns regarding the comic portrayal of excessive drinking.

[citation needed] Smith appeared as Calver Weems in the Don Knotts comedy The Ghost and Mr. Chicken (1966), playing essentially the same town drunk character.

In the television movie, Otis is the town's ice cream truck driver and is reported to have been "sober for years.” Smith later used his Otis Campbell character in commercial spots for the Mothers Against Drunk Driving organization, and he appeared as Otis in Alan Jackson's music video "Don't Rock the Juke Box.” In 1957, Smith played Rollin Daggett in the role of a newspaper man in the early days of Mark Twain in the "Fifteen Paces to Fame" episode of Death Valley Days.

He played the industrialist Hans Spear on CBS's sitcom Hogan's Heroes ("The Swing Shift", season 2, episode 21).

In 1967, he played John Wilson in the 1967 episode "The Man Who Didn't Want Gold" of the syndicated Western series Death Valley Days and Mr. Weber in The Lucy Show.

He reprised the role of the Pancake Man as "Kartoon King" in the 1971 episode of The Brady Bunch, titled "The Winner".

Beginning in the late 1950s with such shows as The Huckleberry Hound Show and Quick Draw McGraw, Smith became one of the most prolific voice actors in Hollywood, eventually working with most of the major studios and production companies, such as Hanna-Barbera, Walt Disney, Warner Bros., the Mirisch Corporation, and Sid and Marty Krofft, with voice roles on such series as The Flintstones in which he mostly did the voices of Texas millionaires such as Fred's rich uncle Tex, Pink Panther, The Many Adventures of Winnie the Pooh, Mickey Mouse, Yogi Bear and Looney Tunes.

According to the book: Space Patrol, missions of daring in the name of early television, "It's rumored that Gene Roddenberry was a huge fan of the show and patterned Star Trek's engineer, Mr. Scott, after McCloud's Scottish sidekick, Taurus".

He was responsible for much of the cast joining the show after he signed on (including Katie Leigh, Will Ryan, Walker Edmiston, Earl Boen, Dave Madden and others), and he continued recording episodes until a few weeks before his death, even while his health deteriorated.

In an Andy Griffith Fan Interview, published after he died, Smith said that Adventures in Odyssey was one of the most gratifying things he had done in his life.

He provided on-screen promotion for 3 Musketeers, United Van Lines, Hickory Farms, Toyota, Green Giant, General Mills, Mattel, Kellogg's, Pizza Hut, Chicken of the Sea, Ivory soap, Doctor Ross Dog Food, Pioneer Chicken, Bell Telephone Company, Coca-Cola, Chef Boyardee and hundreds of other advertising sponsors.

Don Pitts, his longtime agent, said that Smith died at his home in Santa Monica, California, while he was listening to a nightly drama hour on radio.