Sonny William 'Sonny Bill' Williams (born 3 August 1985) is a New Zealand rugby player and heavyweight boxer who has played rugby league and rugby union at the highest levels. He currently plays rugby union for Counties Manukau. He is only the second person to represent New Zealand in rugby union after first playing for the country in rugby league. He is particularly known in both codes for his ability to offload the ball in the tackle and, formerly in rugby league, for his shoulder charges.
Williams made his professional rugby league debut for the Canterbury Bulldogs during the 2004 NRL season. In 2008 he left the Bulldogs mid-season to play rugby union with French club Toulon. In 2010 Williams signed with the New Zealand Rugby Union in a successful bid to play for the All Blacks at the 2011 Rugby World Cup. He played provincially for Canterbury in the 2010 ITM Cup, before being selected for the All Blacks' 2010 end of year tour where he made his Test debut against England on 6 November. In Super Rugby he played for the Crusaders in 2011 and the Chiefs in 2012. Following that, he played briefly for Panasonic in the Japanese Top League before returning to rugby league after signing with the Sydney Roosters for the 2013 NRL season. That year he was judged the world's best rugby league player at the annual RLIF Awards. After playing another season for the Roosters in 2014, Williams returned to New Zealand rugby with Counties Manukau in the 2014 ITM Cup.
From 2009 to 2013, Williams boxed professionally six times, winning all six of his heavyweight bouts before suspending his boxing career to focus on football. Subsequently, he resurrected his boxing career in early 2015. He was formerly the New Zealand Professional Boxing Association (NZPBA) Heavyweight Champion and World Boxing Association (WBA) International Heavyweight Champion.