A distance swimmer, Bill Heusner swam for Northwestern University, winning three Big 10 titles and two NCAA Championships, the 1,500 metre freestyles in 1948-49. At the 1952 Pan American Games Heusner won two relay medals, a gold in the 4x200 freestyle relay and a silver in the 4x100 freestyle relay.
Heusner graduated with a degree mathematics and physics in 1949, later earning a master's degree in physical education, both at Northwestern. He then earned a PhD from the University of Illinois in physical education, physiology and statistics in 1955. Heusner became a physical education professor and swim coach, starting at the University of Minnesota in 1957-62. He then spent 27 years at Michigan State University. He received many honors for his coaching, including the College Swimming Coaches Association of America Service to Aquatics Award, the Michigan Interscholastic Swimming Coaches Outstanding Service Award and the National Interscholastic Swimming Coaches Association Service Award for contributions to the Sport of Swimming.