Foster was named as one of the “ten most outstanding senior men” while serving in the Reserve Officers’ Training Corps. He married Lynnette Estes in 1962 and they had two sons, two daughters who eventually produced eight grandchildren. Foster is a born-again evangelical Christian and a Republican who was a supporter of the George W. Bush administration. He has been an active supporter for a number of religious and conservative causes such as the Private Sector Solutions, LibForAll, and Free Market Cure. Some of his educational causes include the Alliance for School Choice, and All Children Matter.