At the 1928 Winter Olympics in St. Moritz, Sigmund earned a silver medal. At the 1929 FIS Nordic World Ski Championships, he won the ski jumping competition while earning a bronze at the 1930 event. Sigmund also competed in the ski jumping competition at the Holmenkollen ski festival, which first began in 1933. He also competed at the 1932 Winter Olympics in the ski jumping event, but finished seventh due to appendicitis. Additionally, Sigmund wanted to compete in the first alpine skiing events at the 1936 Winter Olympics, though he did not start.