Lars Pettersson played most of his career from 1945-54 with Västerås SK, except a short spell with AIK in 1950-52, but never won a Swedish title with them. Internationally, Pettersson played with the Swedish national team at the 1949, 1950 and 1951 World Championships and at the 1952 Olympics. He won an Olympic bronze in 1952, World Championships silver in 1951, a European title in 1951, and European Championships silver in 1949 and bronze in 1950. He was awarded the Stora Grabbars Märke (Big Boys’ Badge) #95 in ice hockey, a Swedish sports honorary award created in 1928 by Bo Ekelund.