Sergio Siorpaes started competing in 1957 and won his first international medal as a brakeman for Sergio Zardini, with whom he won silver medals in the two-man at the World Championships in 1958 and 1959, both times behind the other Italian bob piloted by Eugenio Monti. Siorpaes then switched to Monti’s team. In 1960 he and Monti won the World Championships in the four-man in his home town of Cortina d’Ampezzo. These World Championships were a substitute for the bob competitions that were not on the 1960 Winter Olympic program in Squaw Valley. At the next year’s World Championships Monti and Siorpaes won both the two- and four-man bob. The team did not compete at the 1962 World Championships but came back to take the title in the two-man again in 1963. After winning two bronze medals at the 1964 Winter Olympics in Innsbruck they had their last great international achievement together winning the 1966 World Championship in the two-man, again in Cortina d’Ampezzo, Siorpaes’ fifth and last world title. At home he won four Italian Championships, three of them in the four-man bob.
Sergio Siorpaes was a trained blacksmith and grandson of the famous 19th century mountaineer Santo Siorpaes. After retiring from active competition, he became assistant coach of the Italian national bobsled team. He invented movable front skids and became one of the most important bobsled builders in the sport’s history.