In 1939, he signed with Warner Bros. and was cast in supporting roles, many times along with James Cagney, in such movies as Cagney’s Yankee Doodle Dandy (1942), as well as with Gary Cooper in Sergeant York (1941) and Irving Berlin, Ronald Reagan, and George Murphy in This Is the Army (1943). In 1950, he was cast against type as a ruthless killer and felon in the film noir Southside 1-1000.

In 1954, actress Lynn Baggett was involved in a collision in Los Angeles while driving a car borrowed from Tobias, and a 9-year-old boy was killed. (Baggett and Tobias were old friends, and she reportedly had been his girlfriend in the 1940s, but at the time of the accident she was the estranged wife of producer Sam Spiegel.) She eventually was acquitted of manslaughter but convicted of felony hit-and-run, and she spent 55 days in jail. The boy’s mother sued Baggett and Tobias in separate court proceedings. They shared responsibility for damages, which amounted to $2,599 ($24,800 today).

Tobias never married and retired from acting in 1977 after reprising his role as Abner Kravitz in a guest appearance on the Bewitched sequel Tabitha.

On February 27, 1980, Tobias died of Bladder cancer at the age of 78 at Cedars Sinai Medical Center in Los Angeles. He is buried in Mount Carmel Cemetery, Glendale, Queens, New York City.