Denys Owen Williams was born in New Malden, Surrey, on 24 February 1918, the son of Robert Owen Williams, a deputy chief clerk, and Ruth Matilda, née Fairclough. He was educated at Surbiton Grammar School, matriculating in 1933. His medical studies were undertaken at St Mary's Hospital, Paddington, where he rowed for the Hospital and became surgical registrar. Subsequently he was senior surgical registrar at Southlands Hospital, Shoreham-by-Sea before being appointed consultant surgeon to the RAF. In that service he was stationed at Ely, Cyprus, Germany and Cosford, attaining the rank of group captain in 1966. He married Joyce Dorothy Barrett, a state registered nurse, on 18 March 1944. They had two sons - Denis, who became a group captain in the RAF, and Richard, who was a colonel in the Royal Artillery - and a daughter, Sara, who became a sign language communicator. He died on 19 December 1995.