John Peter Rhys Williams was born in Cardiff on 2 March 1949 and educated at Millfield School and St Mary's Hospital before qualifying as an orthopaedic surgeon. Having toured Argentina with a Wales XV in September 1968 he gained the first of his 55 caps for Wales against Scotland in February 1969. All but one of his internationals was at full-back but he played as a flanker against Australia in 1978. He scored six tries for Wales and was captain on five occasions. He played club rugby for London Welsh and, latterly, Bridgend. On two British Isles tours to New Zealand in 1971 and South Africa in 1974 he made 30 appearances, including all eight test matches. His 11 games for the Barbarians included the fixtures against South Africa and Fiji in 1970 and New Zealand in 1973.