Kimball was also a jazz trombonist. He founded and led the seven-piece Dixieland band Firehouse Five Plus Two, in which he played trombone. The band made at least 13 LP records and toured clubs, college campuses and jazz festivals from the 1940s to early 1970s. Kimball once said that Walt Disney permitted the second career as long as it did not interfere with his animation work. Kimball appeared on the March 17, 1954, episode of "You Bet Your Life", where Groucho Marx coaxed him into playing his trombone with the house band. He and his partner won $75 in their quiz portion of the show, including one Disney animation question that Kimball answered easily.