Reiner began as a writer and a performer on Your Show of Shows and Caesar's Hour in the 1950s.
Reiner was frequently seen or heard playing the straight man to Mel Brooks' "2000-Year Old Man" character.
In 1961, Reiner created The Dick Van Dyke Show. In addition to usually writing the show, Reiner costarred as variety show host "Alan Brady". The show ran from 1963 to 1966.
Reiner played a large role in the early career of Steve Martin, by directing and cowriting four films for the comedian; The Jerk in 1979, Dead Men Don't Wear Plaid in 1982, The Man With Two Brains in 1983, and All of Me in 1984. In 2000 Reiner was honored with the Mark Twain Prize for American Humor.