Besides his stint on Star Trek, Brian has also made guest appearances in many other television series, including The Untouchables, I Dream of Jeannie, Rawhide, Gunsmoke, and Mission: Impossible. He also starred in his own series, Mr. District Attorney, from 1954 through 1955. He also has a number of films to his credit. Among his earliest was the 1949 drama Intruder in the Dust, for which he received a Golden Globe nomination for Best Supporting Actor. David Brian died of cancer and heart failure in California in 1993 . He was 78 years old.