He was a high school basketball star and went on to play at the University of Wisconsin-Madison from 1926 to 1930. While a player at Wisconsin, he was voted twice All-Big Ten Conference and helped lead Wisconsin to a 43-8 three year record under Hall of Fame coach Doc Meanwell. He was named to the All-America team in his senior year.
After college Foster played pro ball with the Oshkosh All-Stars. He had an immediate impact. In 1930, just after the college season ended, he teamed up with fellow Big Ten star (and also a future Hall of Famer) Branch McCracken to lead the All-Stars to a 30-23 victory over the Chicago Majestic and the Midwest professional championship. He went on to play with pro teams in Milwaukee and Chicago.
After his playing career, Bud Foster began coaching. In 1933 he was named coach of Wisconsin's Freshmen team. The following year he became the head coach of the University of Wisconsin-Madison men's basketball team where he served from 1934 to 1959. His Wisconsin team won the 1941 NCAA championship.
Foster served as President of the National Association of Basketball Coaches (NABC).
In 1964 Bud Foster was enshrined in the Naismith Memorial Basketball Hall of Fame as a player. He is also a member of the Helms Basketball Foundation Hall of Fame, the Wisconsin State Athletic Hall of Fame.