Vilém Loos was a leading goal scorer in Czechoslovakia and Bohemia in the years around World War I, possessing a hard and accurate shot. He played for SK Slavia Praha from 1913-29, missing the 1914-19 years due to the war. In addition to his two appearances at the 1920 and 1924 Olympics, he played at the European Championships in 1921-23 and 1925-27, winning gold medals in 1922 and 1925, silver medals in 1921 and 1926, and a bronze medal in 1923. Although he was a right winger, Loos played one minute in goal at the 1927 Europeans. Loos also played football for SK Slavia Praha and Czechoslovakia, competing for the national team at the 1919 Inter-Allied Games. Vilém Loos was the younger brother of Josef Loos, also an international ice hockey player.