John Patrick O'Shea was born in Weston-Super-Mare on 2 June 1940 and educated at Lewis School, Pengam, and St Luke's College, Exeter. In 1958 he played three times for the Welsh Secondary Schools. At senior club level he played for Newbridge, Penzance-Newlyn and Cardiff. His 213 games at prop for Cardiff included the victory over Australia in 1966 and as captain against South Africa in 1969. He also played for East Wales in the 3-all draw against New Zealand in 1967. He gained five caps for Wales in 1967 and 1968 and toured South Africa with the British Isles in 1968 when he played in eight matches, including one test. He returned to South Africa with the Barbarians in 1969 and was captain against Rhodesia. John O'Shea later emigrated to Australia.