Benjamin Kubelsky was born February 14, 1894, in Chicago, Illinois, to Emma Sachs Kubelsky, whose husband, Meyer Kubelsky was a Jewish haberdasher in Waukegan. Although this was long before the age of the automobile, Emma didn't want her son, whom she knew would become famous, to be born in the Podunk town of Waukegan. His parents came to the United States from Lithuania and did everything in their power to make their son famous, starting with violin lessons at age six.
He was playing professionally at age 17 (he had been expelled from high school for being a poor student, much to his father's dismay.) In 1911, he began playing for the Marks Brothers (later known as the Marx Brothers). He met their cousin, Sadye, whom would later become his wife and adopt the stage name, Mary Livingstone (pronounced Livingston). He also did some other musical work traveling with various musicians and orchestras.
He joined the U.S. Navy during the First World War and spent the entire period at the Great Lakes Naval Base near his home. After his discharge, he began performing comedy under the name Ben K. Benny. This sounded too close to a popular bandleader at the time named Ben Bernie. So, he adopted the name, Jack Benny. Jack (or Jackie) is a slang term meaning sailor, since he was a sailor during the war.
In 1922, he had a Passover seder with Zeppo Marx (spelling now changed) and he met his distant cousin, Sadye again. They married in 1927 and she would adopt whatever name her character was in whatever performance they were involved in. For example, in Jack's first talking motion picture for Warner Brothers, a short called Bright Moments (only the soundtrack survives), she was Marie Marsh.
In 1932, Jack did his first radio program. It was a musical program in which he gave the impression that he didn't think much of his talents. This evolved into a miserly spendthrift. His wife became Mary Livingstone, a girl from New Jersey (actually, Sadye Marks was born in Washington State and grew up in British Columbia). There would be several announcers, band leaders, singers, and other players. The best known ensemble included Jack, Mary, Don Wilson (announcer), Rochester Van Jones (played by Eddie Anderson), bandleader Phil Harris (actually a "front;" the band was really led by Mahlon Merrick), and singer Dennis Day. During its last five years on radio, Phil Harris was replaced by Bob Crosby, who was also a front. Mahlon Merrick was Jack Benny's orchestra leader from 1936 until his death in 1969. Mahlon had met Mary's brother, Hilliard Marks, when they were students at Washington State College. Mahlon wrote the Washington State fight song, as well as the Gillette Look Sharp March.
In 1950, while still busy with radio, Jack began doing television for CBS. The last radio program aired in May 1955, although there would be reruns for the next five years after that. Jack stayed on CBS television until 1965, and he did some periodic specials after that. The TV series was much like the radio series, except that Mary didn't appear after 1958. For a while, their daughter Joan took Mary's place and then there was no one. He later appeared on NBC until a few months before his death.
Jack died of pancreatic cancer at the age of 80 on December 26, 1974, at his home in Beverly Hills, California. The cancer had only been diagnosed in October.
Jack's close friends included George Burns, Fred Allen, Bob Hope, and Frank Sinatra. All these men, except Fred Allen (who died in 1956), were present at his death.