He first played for Llanelli RFC in 1970 and was a member of the team that beat a formidable touring All Blacks side in October 1972, eventually going on to captain the club for two seasons from 1980 to 1982. He made his first appearance for Wales against France in 1975 and played in two Grand Slam winning sides, usually as a centre but sometimes as a winger. Gravell was selected to play for the British and Irish Lions in their 1980 tour of South Africa; he came on as a substitute in the first test and was in the starting line up for the next three tests. In the second test at Bloemfontein, Gravell scored his second international try, though the tourists lost 26–19 to the South Africans.