In 1946, he portrayed "Johnniekins" in Margie with Jeanne Crain. The following year, he starred in the film noir The Brasher Doubloon, with George Montgomery.
Throughout his life, Janis has striven to keep traditional jazz alive. In 1949, Janis put together a band of aging jazz greats ("all of the guys that I idolized"), consisting of James P. Johnson (piano), Henry Goodwin (trumpet), Edmond Hall (clarinet), Pops Foster (bass), and Baby Dodds (drums), with Janis on trombone. In the late 1970s, Janis' formed the Beverly Hills Unlisted Jazz Band, which appeared multiple times on the Tonight Show Starring Johnny Carson and made eight sold-out performances at Carnegie Hall.
In 1953, he played eldest son Edward on the sitcom Bonino . He later appeared in an episode of Get Smart playing a KAOS agent, guest starred as a dance marathon emcee on The Golden Girls, and appeared in the sci-fi sitcom Quark. He was featured in The Buddy Holly Story and in the Goldie Hawn comedy The Duchess and the Dirtwater Fox. He also made a brief appearance as himself in the jazz bar scene from Nothing in Common.
