Besides the gold medals with world records in the 1,500m, 5,000m and 10,000m at the 1994 Olympic Games in Lillehammer, he also won 1,500m gold and 10,000m silver in 1992 Games in Albertville. Other major achievements included three overall world championship titles–in 1990, 1991, and 1994. Koss could not be recognized as such future sports hero in his younger years. In 1987 he became a national junior champion speedskating, but he could not compete with the top skaters in the 1986 and 1987 World Junior Championships. At his debute with the seniors at the World Championships in Medeo 1988, he failed to qualify for the final distance. In 1989 he finished 15th in the European Championship, but he finished 8th in the World Tournament that same year. In 1990 he broke through at the World Championships in Innsbruck, Austria, which he won. He would remain at the top of world by winning the World Championship again in 1991 and 1994 and finishing 2nd in 1993 and 3rd in 1992. He won the European Championships in 1991 and finished 3rd in the next three editions.