Clarke started his pro career as part of the all conquering Bristol Academy under Paul Hull.
He was a tall long-striding and elusive player, excelling at full back for England Under 21s in a Grand Slam season.
He was named Young Player of the Year in 2003/04, normally operating at full back, before a switch to centre in 2005 saw his career hit new highs.
Clarke was also hugely significant for Saints during the 2009/10 season with his nine tries in all competitions the second highest tally in the squad, and his play alongside James Downey earned him a call from the England Saxons for their Six Nations games against Ireland and Italy.
On 27 December 2013, Clarke was loaned out to Yorkshire Carnegie who compete in the RFU Championship for the remainder of the 2013–14 season.