Foster prepped at Taft High School in Canoga Park, California and Shawnee Mission West High School in Overland Park, Kansas. Foster was a first round pick of the Miami Dolphins in the 1982 NFL Draft. He was a two-time Pro Bowler, in 1985 and 1986, and played in two Super Bowls.
He retired with the San Francisco 49ers in 1993.
He is only offensive lineman to have blocked for Joe Montana, Steve Young, and Dan Marino. He also caught a touchdown pass from Dan Marino.