Dino Paul Crocetti was born into an Italian-American family in Steubenville, Ohio. He left school aged sixteen and had a variety of jobs before changing his name and achieving moderate success as a singer in the New York club scene. He first teamed up with Jerry Lewis July 25, 1946 at Club 500 in Atlantic City, New Jersey and the two created a successful stage comedy routine, the duo made their first film together in 1949 with My Friend Irma and in 1951 they starred in the hit At War with the Army which established the formula for their thirteen following films. On television the duo debuted in 1950 on The Colgate Comedy Hour, a variety show that they would occasionally host from 1950-1955. The partnership with Lewis broke up on July 24, 1956 and Martin surprised many when he went on to further success on his own.
In the 1960s he was part of the Rat Pack and made a number of successful films with them. He also starred in a series of four films as a secret agent, Matt Helm (1966-1969) and from 1965 until 1974 he hosted the weekly The Dean Martin Show on NBC. In the 1970s his poor health and declining popularity generally restricted him to the stage, he finally retired completely only in 1988 when he became ill during a concert tour with surviving Rat Packers Frank Sinatra and Sammy Davis, Jr. He appeared in fifty-one films in all.
He was married three times and had eight children, one by adoption. Personal tragedy struck on March 21, 1987 when his 35-year-old son, Dean Paul Martin, Jr, an actor, singer (in the group Dino, Desi, & Billy), and former tennis pro, was killed in plane crash.