Humphreys joined Leicester Tigers in 2005 from Belfast Harlequins. His first outing in Tigers stripes was at the Middlesex Sevens Tournament at Twickenham in August. During October 2006 Humphreys was loaned out to first division Leeds where he made 4 appearances, scoring 2 tries and a drop goal. On his return to the Leicester first team he guided the Tigers to a victory away at Wasps with a mature display. After more assured performances, and a hamstring injury to Andy Goode, Humphreys was selected to play Munster at Thomond Park in a decisive Heineken Cup pool game. After his brilliant performance in a high tempo match he was the selected for his Ireland A début against England Saxons at Ravenhill, in his native Ulster.
In April 2008, after falling out of favour at Leicester, Humphreys signed for Ulster to replace his retiring brother.