Taking a year away from college, he won a silver medal as a member of the U.S. ice hockey team at the 1956 Winter Olympics, after turning down a professional-contract offer from the National Hockey League's Montreal Canadiens (Cleary opted to go into the insurance business instead and made more money than he probably would have in the NHL). At the 1959 World Ice Hockey Championships, he won the IIHF directorate award for best forward. At the 1960 Winter Olympics, in Squaw Valley, California, Bill and his brother Bob teamed up to win a gold medal with the U.S., with Bill leading the team in scoring through the tournament with 14 points.