Richard Cromwell's starring breakthrough came in “The Lives of a Bengal Lancer” (1935), in which he shared top billing with Gary Cooper and Franchot Tone. The movie received a best picture Oscar nomination; the award went to “Mutiny on the Bounty.”
He made other notable appearances in "Tol'able David" (1930), "Jezebel" (1938) and "Young Mr. Lincoln" (1939).
Cromwell was also an artist and writer, the latter careers pursued under his given name Roy Radabaugh. As an artist, he gained a reputation for his masks of motion picture personalities, as well as oil portraits.
Cromwell was married for eight months to actress Angela Lansbury in 1945. Years later in her authorized biography, Lansbury said she didn't find out until years after their divorce that Cromwell was gay.