His father was John Levin Johansson (1886-1923), a son of Johan Ludvig Persson who later changed his name to John Hasselgård; his mother was Linda Köhler (1893-1979), a daughter of Magnus Wilhelm Köhler.
Having achieved international renown, he moved in 1947 to New York City, and played there on 52nd Street with Jack Teagarden and Max Roach.