After college, Foster played professionally with the Oshkosh All-Stars. 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, Foster was named freshman coach of basketball at Wisconsin in 1933. He succeeded Doc Meanwell as head coach a year later, and remained as head coach until 1959. His Wisconsin team won the 1941 NCAA championship.
National champion
Postseason invitational champion
Conference regular season champion
Conference regular season and conference tournament champion
Division regular season champion
Division regular season and conference tournament champion
Conference tournament champion