She began to emerge as a walker internationally in the early 1970s, starting with a third place at the Nordic Race Walking Championships junior race in 1971, then two consecutive wins in the category in 1973 and 1975. Her first senior title at the event came over 5 km in 1977, when she beat Britt Holmquist and Norway's Thorill Gylder. The 1975 IAAF World Race Walking Cup and 1977 IAAF World Race Walking Cup both featured invitational, non-official women's races and she showed herself to be among the world's best with a runner-up finish to fellow Swede Margareta Simu at the first race, then beating both Simu and Carol Tyson to win the 1977 race. She missed the first official women's championship in racewalking held in 1979. She competed at the WAAA Championships in Britain in 1980 and was runner-up to Irene Bateman over 5000 m. Her career peaked at the 1981 IAAF World Race Walking Cup, where she became the second ever women's world champion in racewalking, defeating the whole field by nearly twenty seconds. The Swedish team was narrowly beaten by one point to the women's team title. She attempted to defend her title at the 1983 IAAF World Race Walking Cup, but ending the competition in fifth place. Wit Gustavsson being their top performer, Sweden's women also fell down the team rankings into fourth place. She appeared at the 1986 European Athletics Championships and in the 10 km walk—the first ever to be held for women at the European Championships—she ranked third for a bronze medal behind Spanish athlete Mari Cruz Díaz and Ann Jansson. She married fellow race walkerEnrique Vera Ibáñez, who migrated from his native Mexico to settle with her in Sweden. Her husband gained Swedish citizenship and later represented his adoptive country at the 1991 World Championships in Athletics. The couple had a child in 1985, Ato Ibáñez, who himself has since gone on to represent Sweden in race walking. The couple were later divorced. She had a second child in 1990, Perseus Karlström, who also became a professional racewalker. Gustavsson continued on as a walker and was the over-45 European Indoor champion in 2005 and broke the over-50s world record in the indoor 3000 m in 2012.
