Having impressed during his brief loan spell, scoring three goals in nine appearances, Guy signed a permanent deal with Dave Penney's side prior to the start of the 2005–06 season.
In early 2009, Guy spent a month's loan spell at Hartlepool United, but he struggled to make an impact at Victoria Park, and was sent back to Doncaster after he picked up an injury.
On 19 May 2010 Guy joined League One outfit Milton Keynes Dons on a free transfer, following his release by Doncaster.
[2] Guy returned to his parent club following Oxford's 2–2 draw with Burton Albion on 10 September 2011, having scored once in six appearances for the U's.
[3] On 6 January 2012, Guy was released from his contract with the MK Dons and during January had a trial with Scottish Premier League club St Mirren; on 24 March 2012, he had signed a pre-contract agreement with the club, linking up again with Tommy Craig, who coached Guy at Newcastle United.
Guy Scored his second goal for the club in a Scottish league cup match at home against Ayr United which finished 5–1 to St Mirren.