He previously played in the Premier League for Fulham, in the Football League for Yeovil Town and Bristol City and in the Scottish Premier League for Kilmarnock. He represented England at Under-16 and Under-17 level, played for Fulham, mainly playing when injuries prevent more experienced players from playing. However, he made a couple of appearances during his breakthrough season, 2004-2005, his debut coming against Southampton at Saint Mary"s on 5 January, albeit with Fontaine on the pitch for only a few minutes.
The game was drawn 3–3.
Fontaine also spent some time at Yeovil Town earlier in that season. His loan move was initially for a single month, but later was extended by a further two months.
He enjoyed a further loan spell in the latter part of the 2004-2005 season with Kilmarnock in the Scottish Premier League. After being brought to Yeovil by then manager Gary Johnson, Fontaine then went back to Fulham until he was brought to Bristol City on loan by his former Yeovil manager Johnson.
The loan spell was made permanent at the end of that season with Fontaine signing a two-year contract, with City having to pay Fulham an undisclosed fee through tribunal.
Fontaine signed a new deal with Bristol City on 12 January 2012 to keep him at the club until the end of 2014 season, stating his ambition is to be the clubs captain on a permanent basis. On 2 September 2013, Fontaine joined Championship side Yeovil Town, for a third spell, on loan until January 2014. At the end of the 2013-2014 season, Fontaine was released by Bristol City.
On 26 August 2014, Fontaine joined Scottish Championship side.
He made his debut the same day, in "s 3–2 victory against Dumbarton in the Scottish League Cup. Fontaine made 38 appearances and scored two goals in the 2014-2015 season.
In June 2015, he signed a two-year contract with.
A key member of the 2006-2007 promotion team and flourished once more at Championship level, he became centre stage when his goal against Wolves in November left his manager Gary Johnson red-faced – having previously told his defender he would "bare my backside in Burton"s window" if he found the Netto.