French-Canadian boxer Jack Delaney was born in Quebec on March 18, 1900. His family relocated to Holyoke, Massachusetts. At the age of 19, Delaney began to fight, compiling a starting record of 27 out of 30 matches. In 1924, Delaney defeated Tommy Loughran, who would later go on to win the light heavyweight title. Shortly thereafter, Delaney faced Paul Berlenbach in a match that ended in the fourth round after Delaney knocked down Berlenbach twice. He faced Berlenbach numerous times in his career, the most notable meeting being the light heavyweight title match.
Delaney successfully secured the title, which he relinquished in 1927 to contend for the heavyweight championship. He was less successful in the heavyweight weight class, the loss in momentum partly due to an injured hand. Delaney faced Jack Sharkey in a controversial match, as it was speculated that Delaney was drunk. The match ended in the first round when Sharkey knocked Delaney out cold. Delaney retired shortly thereafter, although he attempted a short-lived comeback in 1932. In 1948, Jack Delaney died of cancer.