A back row forward, he played his club rugby for Swansea, Neath, Cardiff, London Irish and Northampton and has 28 international caps.
[2][3] After three seasons with Cardiff, Williams joined London Irish in 2000, and won the Powergen Cup with the side in 2002, starting in the second row in a 38–7 win over Northampton.
[10] In 2002, Williams earned a recall to the national side for a friendly against the Barbarians, and joined the team on the 2002 Wales rugby union tour of South Africa.
[12] After retiring as a player, Williams joined Coventry in 2004, and became coach following the resignation of Director of Rugby John White.
[15] In 2007, Williams departed the Bees to join Ulster as assistant coach, replacing Allen Clark.