He attended Cowbridge Comprehensive School and Ysgol Gyfun Bro Morgannwg and he is a fluent Welsh speaker.

[2] A senior figure in the Cardiff team, Williams has captained the side on numerous occasions, the first coming against Montpellier in 2015.

[8] In June 2011 he was called into the Wales 45-man training squad for the 2011 Rugby World Cup[9] following the suspension of Mike Phillips.

Williams was selected in the final squad for the World Cup, and scored two tries in the pool stages, as Wales ultimately finished fourth in the tournament.

For the 2012 Six Nations, Williams maintained his place in the Welsh team, coming off the bench as Wales secured a Grand Slam against France on 17 March 2012.