Fos Williams was born on 21 February 1922 in Quorn, South Australia, Australia. He was married to Veronica Ganley. He died on 1 September 2001 in Novar Gardens, South Australia, Australia.
Became a Member of the Order of Australia (AM) on 26 January 1981 (which was also his 25th wedding anniversary) for his services to the sport of Australian football.