A two-time amateur champion of the Netherlands, Ko Willems came to the 1924 Paris Olympic with his sights set on the 50 km track race. Together with his compatriot Jan Maas, they had set out the race strategy: Maas would try to escape and either win or tire the competition, allowing Willems to win the final sprint. Their plan worked out perfectly, and Willems won the gold, the second Dutch cyclist after Maurice Peeters. Willems then turned professional, but had an anonymous career, retiring in 1932. He was better known for his bike store near the Amsterdam Olympic Stadium. His two sons, Hans and Bob helped him in his store and workshop. Like his father, Hans Willems also became an Olympian, competing in the 1964 Olympics as a sailor. In 1963, Hans won a bronze medal in the Finn Gold Cup, as the World Championships in that boat are known.