Johan Wallner first drew attention to himself in 1982 when he won gold in slalom and bronze in giant slalom in Auron at the Junior World Championship, which was held for the first time . The following year gold was added in the giant slalom. He won his first points in the World Cup on February 23, 1983 with 14th place in the slalom in Tärnaby . Wallner competed in the World Cup until December 1997 and won his only World Cup race on January 14, 1986, a slalom in Berchtesgaden . Otherwise he achieved three more podium places, but all in the giant slalom, and a total of 23 top 10 placements.
From 1985 to 1997 Johan Wallner took part in six world championships , only in 1989 he was not at the start. He achieved his greatest successes at the world championships in 1991 in Saalbach-Hinterglemm and in 1993 in Morioka when he won the bronze medal in the giant slalom. In 1991 he also achieved fifth place in the Super-G - a discipline in which he could never score in the World Cup. From 1984 to 1994 he also took part in four Winter Olympic Games . While it only started in giant slalom in 1984, it was used in both giant slalom and slalom in 1988, 1992 and 1994. In his total of seven Olympic starts, he only reached the finish line twice, in 1988 in Calgary as 16th in the giant slalom and in 1994 in Lillehammer as 25th in the giant slalom. Johan Wallner was one of the most successful participants at the Swedish Championships . From 1983 to 1997 he was Swedish champion ten times - four times in giant slalom and twice each in slalom, combined and super-G.
After a disappointing start to the season, he announced his resignation at the end of December 1997.