Lars-Gunnar Pettersson started his hockey career in 1976 with Luleå HF. From 1980-87 he played with IF Björklöven and then from 1987-94 finished his career by playing again with Luleå HF. With Björklöven, Pettersson won a Swedish title in 1987 and was the leading goalscorer at the Swedish Championships in 1987 and 1989. Pettersson was drafted by the Edmonton Oilers of the NHL in 1980, but never played in North America.
Internationally, Pettersson played at the 1988 Winter Olympics, at the 1985, 1986 and 1987 World Championships and at the 1987 Canada Cup. He won an Olympic bronze in 1988, was World Champion in 1987, won silver at the 1987 World Championships and another silver at the 1986 European Championships. He was awarded the Stora Grabbars Märke (Big Boys’ Badge) #139 in ice hockey.
Sweden