Born Anita Belle Colton in Chicago, Illinois on October 18, 1919, she later changed her name and, in the late 1930s, began singing in a jazz club called the Off-Beat. In 1941, she joined drummer Gene Krupa's band; and, a few weeks later Krupa hired trumpeter Roy Eldridge. The O'Day-Eldridge duet "Let Me Off Uptown" became a huge hit. That year, Down Beat magazine named O'Day "New Star of the Year." In 1942, the magazine selected her as one of the top five big band singers.
O'Day later joined Stan Kenton's band. In the late 1940s, she teamed up with drummer John Poole and continued to perform with him for the next 32 years. Her album Anita, recorded for producer Norman Granz's new Verve label, was a best seller. O'Day performed in festivals and concerts with such iconic musicians as Louis Armstrong, Dinah Washington, Georg Shearing, and Thelonious Monk. She made a notable appearance in Jazz on a Summer Day, a documentary filmed at the Newport Jazz Festival in 1958.
During the 1960s, she continued to tour and record despite her addiction to heroin. In 1969, she almost died from an overdose, but she later overcame her addiction and returned to work. She wrote candidly of her life in her 1981 autobiography High Times, Hard Times.
O'Day's last recording was Indestructible Anita O'Day. A documentary, Anita O'Day -- The Life of a Jazz Singer, will be released in 2007.