Korman, who was of Russian Jewish descent, was born in Chicago, Illinois, the son of Ellen (née Blecher) and Cyril Raymond Korman, a salesman. He served in the United States Navy during World War II. After being discharged, he studied at the Goodman School of Drama. He was a member of the Peninsula Players summer theater program during the 1950, 1957, and 1958 seasons. Korman made his first TV appearance as a comically exasperated public relations man in a January 1961 episode of the CBS drama Route 66. He appeared on numerous television programs after that, including the role of Blake in the 1964 episode “Who Chopped Down the Cherry Tree?” on the NBC medical drama The Eleventh Hour and a bartender in the 1962 Perry Mason episode, “The Case of the Unsuitable Uncle.” He frequently appeared as a supporting player on The Danny Kaye Show from 1963 through 1967. He was cast three times, including the role of Dr. Allison in “Who Needs Glasses?” (1962), on ABC’s The Donna Reed Show. He also guest-starred on the NBC modern western series, Empire. From 1964 to 1966, he appeared three times in consecutive years on the CBS comedy The Munsters starring Fred Gwynne and Yvonne De Carlo. During the 1965-1966 season, Korman made regular appearances on ABC’s The Flintstones as The Great Gazoo, in its final season on network television. It was his work on The Carol Burnett Show, beginning in 1967, which brought Korman his greatest fame. Korman was nominated for six Emmy Awards for his work on The Carol Burnett Show and won four times – in 1969, 1971 (for “Outstanding Achievement” by a performer in music or variety), 1972 and 1974. He was also nominated for four Golden Globes for the series, winning in 1975.

While appearing on The Carol Burnett Show, Korman gained further fame by appearing as the villainous Hedley Lamarr in the 1974 film Blazing Saddles. He also starred in High Anxiety (1977) as Dr. Charles Montague. In 1980 he played Captain Blythe in the Walt Disney comedy, Herbie Goes Bananas. In 1981 he played Count de Monet in History of the World, Part 1. In later years he did voice work for the live-action film The Flintstones as well as for the animated The Secret of NIMH 2: Timmy to the Rescue. He also starred in the short-lived Mel Brooks TV series The Nutt House, and in his final Mel Brooks film, as the zany Dr. Seward, in Dracula: Dead and Loving It. He also reunited with fellow Carol Burnett Show alumnus Tim Conway, making guest appearances on, and in 1981 becoming a regular cast member of, Conway‍ ’​s 1980-1981 comedy-variety series The Tim Conway Show. The two men later toured the country reprising skits from the show, as well as performing new material. A DVD of new comedy sketches by Korman and Conway, Together Again, was released in 2006. Korman and Conway had been jointly inducted into the Television Hall of Fame in 2002. Korman died at the age of 81 on May 29, 2008, at UCLA Medical Center, as the result of complications from a ruptured abdominal aortic aneurysm he had suffered four months earlier. His grave is at Santa Monica’s Woodlawn Cemetery.