Alsgaard got his international breakthrough in the Lillehammer 1994 Winter Olympics winning the 30 kilometre freestyle event. In total, Alsgaard won 15 medals in the Winter Olympics and FIS Nordic World Ski Championships, making him one of the most successful skiers of all time. Alsgaard won at least one gold medal at every Olympic Games and World Championships that he participated. Alsgaard retired from racing after the 2003 World Championships.