Hickie made his senior debut for Leinster on 6 September 1996 in a friendly match away to a Genoa President's XV and his senior Irish debut on 1 February 1997 against Wales. He earned 51
caps for Ireland, scoring 29 tries for Ireland and held the Irish try-scoring record until his friend and
Leinster colleague
Brian O'Driscoll broke it in 2008. He missed out on selection to the
2001 British & Irish Lions tour to Australia. He overcame a ruptured Achilles tendon sustained during the 2003 World Cup and forced his way back into the Irish line-up, apparently losing nothing of his pace. His solid form in the
2005 Six Nations earned Hickie a call-up for the
2005 British & Irish Lions tour to New Zealand and the Leinster back became a key member of the successful midweek team. Hickie suffered many injuries throughout his career. In October 2005, in the week coming up to the European Cup, he dislocated his right
fibula following a training ground accident and missed the autumn tests. This injury kept him out of the 2005 autumn international series and he subsequently lost his place on the Irish team to Ulster's Andrew Trimble for the duration of 2006, despite his excellent form for Leinster. This was best captured in his try in Leinster's
Heineken Cup quarter-final match against
Toulouse in France which saw him run the length of the pitch partnered by
Gordon D'Arcy to score in the corner. An injury to Trimble saw Hickie retake the number 11 shirt for Ireland against Australia in the 2006 Autumn tests where he scored a notable try, beating four Australian defenders with his trademark 'dancing' footwork. Making the number 11 jersey his own, and scoring two further tries in the 2007 Six Nations, Hickie was first choice left wing for the 2007 World Cup, after which he retired. Brian O'Driscoll respectfully mentioned Denis & his contribution to Leinster Rugby in his after match interview after the final whistle in the 2009 Heineken Cup Final which Leinster won. Hickie is a committee member of the
rugby sevens club,
Shamrock Warriors RFC. ==Miscellaneous==