Thomas Dorsey was born in Shenandoah, Pennsylvania and is the younger brother of Jimmy Dorsey.
He worked with many bands in the New York City area starting in the 1920s, including the bands of Rudy Vallee, Vincent Lopez, and Paul Whiteman. With brother Jimmy he lead the Dorsey Brothers Orchestra until they split up in 1935.
Tommy Dorsey formed his own band which was very successful.
The band featured trumpeters Bunny Berigan and Charlie Shavers, arranger Sy Oliver, and singers Jo Stafford and Frank Sinatra. Sinatra achieved his first great success as a vocalist in the Dorsey band and claimed he learned breath control from watching Dorsey play trombone.
Pan American World Airways's president Juan Trippe was a member of his band in 1940.
By Dorsey's own admission, his trombone style was heavily influenced by that of Jack Teagarden.
Tommy Dorsey died suddenly at his home in Greenwich, Connecticut.