Williams was born in Carshalton, London. His professional career began with West Ham United in April 2000 when he joined the club from Walton & Hersham for a fee of £40,000. He went on loan to Peterborough United in March 2001, without having made his senior debut, and the move was made permanent during the summer. He stayed with the Posh for one season, before moving to Birmingham City for a fee of £350,000.
His career stalled at St Andrew's, playing just four games for Birmingham, and, after two loan periods at Queens Park Rangers, scoring once against Huddersfield Town, he rejoined Peterborough United, initially on loan, later joining permanently. In May 2004 Williams went to Barnsley on a free transfer.
Williams qualifies for Cyprus through his mother, and has one international cap to date, which came in 2006.
On 31 December 2007 Williams joined Peterborough United for the third time, initially on an emergency loan to make him available for the match on New Year's Day, for which he was an unused substitute. The loan was converted to a two-year permanent deal two days later.
On 9 November 2009, Williams rejoined Championship side Queens Park Rangers on a short-term loan deal, with a possible view to sign permanently in the January transfer window. This did not happen in the end and he returned to Peterborough during January 2010.
After a pre-season trial, Williams joined Championship club Bristol City on a six-month contract on 5 August 2010.
On 14 February 2011, he joined League One side Walsall on a deal until the end of the season. He scored once for Walsall in a 1–1 draw with Oldham Athletic. In August 2011, Williams played one match in the Conference for Kettering Town, a 3–0 defeat away at Mansfield Town. He signed for Notts County in August 2012 on a short-term deal, and was released in January 2013 when his contract expired.
In February 2014, Williams was one of a number of foreign signings made by Vanuatu club Amicale to strengthen their team ahead of the 2013–14 OFC Champions League campaign.
