Born in Chicago, Illinois, USA, to a Jewish family, he began working in vaudeville in 1922 as the straight man for his brother's jokes. He was also a cellist, a skill which he used throughout his career. By 1924, he was working in a speakeasy operated by Al Capone. After being caught in a gunfight, Amsterdam moved to California and sought work writing jokes. His enormous repertoire and ability to come up with a joke on any subject earned him the nickname "The Human Joke Machine." He sometimes performed with an actual machine on his chest, hanging by a neck strap. When he turned a hand crank on the gadget and paper rolled out, he would then read the machine's joke -- although the paper was blank.
The Morey Amsterdam Show ran on CBS television from December 1948 to March 1949 and on DuMont from April 1949 to October 1950. Among Morey's regular guests was a song-and-dance man named Art Carney. The cigarette girl was future author Jacqueline Susann, wife of the producer of the show, Irving Mansfield. Jazz musician Johnny Guarneri led the band. Also in 1950, he briefly hosted the comedy-variety show, Broadway Open House, television's first late-night entertainment show, on NBC.
Amsterdam's most famous role is comedy writer Buddy Sorrell on The Dick Van Dyke Show (1961-66), a role suggested for him by his friend Rose Marie, who also appeared on the show. Amsterdam wrote lyrics for the show's theme song, which were never heard on the air but have been performed by Dick Van Dyke in concert.
Amsterdam was an occasional panelist on Match Game during the 1970s. He appeared as a small-time criminal in several episodes of the soap opera The Young and the Restless in the 1990s. Amsterdam and Rose Marie later appeared as panelists on The Hollywood Squares and guest-starred together in a February 1996 episode of the NBC sitcom Caroline in the City (his final television appearance).