Along with his twin brother Hans, Stig Andersson-Tvilling took up ice hockey in 1947. Like his brother, he played his entire career from 1947-61 with Djurgårdens IF and won seven Swedish titles with them (1950, 1954, 1955, 1958-61). Internationally, Andersson-Tvilling earned 84 caps with the Swedish national team. He won an Olympic bronze in 1952, was a World Champion in 1953, won silver at the 1951 World Championships and bronze at the 1954 World Championships. He was also a European Champion from 1951-53, while taking silver at the 1954 and 1956 European Championships and bronze at the 1955 European Championships. Andersson-Tvilling was also an accomplished football player, earning one cap with the Swedish national team. He was awarded the Stora Grabbars Märke (Big Boys’ Badge) #45 in ice hockey, a Swedish sports honorary award created in 1928 by Bo Ekelund.