[citation needed] After his wife's death in 1937, Coburn relocated to Los Angeles, California, and began film work.

He won an Academy Award for Best Supporting Actor for his role as a retired millionaire playing Cupid in The More the Merrier in 1943.

[citation needed] Other notable film credits include Of Human Hearts (1938), The Lady Eve (1941), Kings Row (1942), The Constant Nymph (1943), Heaven Can Wait (1943), Wilson (1944), Impact (1949), The Paradine Case (1947), Everybody Does It (1950), Has Anybody Seen My Gal?

He usually played comedic parts, but his roles in Kings Row and Wilson showed his dramatic versatility.

[4] In the 1940s, Coburn served as vice president of the Motion Picture Alliance for the Preservation of American Ideals, a group opposed to leftist infiltration and proselytization in Hollywood during the Cold War.

[6][7] A staunch Republican, Coburn supported Thomas Dewey in the 1944 United States presidential election.