Growing up in a show-business family, Lewis began following in his parents' footsteps as a performer from a very young age. He made his debut at the age of 5, singing "Brother, Can You Spare a Dime?" at New York's "Borscht Belt" nightclubs in the Catskill Mountains.
A decade later, at the age of 15, Jerry Lewis dropped out of high school to pursue a full-time career as a performer. In 1945, a 19-year-old Lewis met a young crooner named Dean Martin while performing at the Glass Hat Club in New York City. A year later, when Lewis was performing at the 500 Club in Atlantic City and another performer suddenly quit, Lewis suggested that the club book Dean Martin as a replacement. On July 25, 1946, Martin joined Lewis as a performer at the 500 Club, and one of the greatest partnerships in the history of American show business was born.Their act began with Martin singing a song only to be interrupted by Lewis, with the routine soon devolving into a hilarious improvised sequence that included ad-libbed insults, food fights and frequent banter with the audience.
In 1949, the pair landed their own regular radio comedy show, The Martin and Lewis Show, and after Paramount producer Hal Wallis saw them perform at the Copacabana nightclub in New York, he booked them both to a film contract. Martin and Lewis made their big-screen debut in the 1949 film My Friend Irma, earning rave reviews.
Over the next decade, Dean Martin and Jerry Lewis made 16 films together, including My Friend Irma Goes West (1950), The Stooge (1952) and Hollywood or Bust (1956). The pair also made frequent television appearances on the Ed Sullivan Show and The Colgate Comedy Hour.
In addition to his prolific career as an entertainer, Lewis has been active in the fight against muscular dystrophy. Until 2011, he served as the chairman of the Muscular Dystrophy Association and hosted an annual telethon that has raised nearly $60 million a year in donations.