He made his debut for Ireland as a 19-year-old in the Rugby World Cup in 1999, playing on the wing against Romania.
He moved successfully to the centre for Leinster and Ireland in 2004, winning a Triple Crown with Ireland and it was a move which saw his representative career for Ireland accelerate to the point where he has become the second most-capped centre in Irish history, behind his long-time playing partner Brian O'Driscoll.
He represented Ireland in a further two Rugby World Cups, in 2007 and the recent tournament in New Zealand, and was an integral part of the Ireland team that won the Six Nations Grand Slam in 2009.
That same year he won his first Heineken Cup with Leinster and was part of the side that again won the trophy in 2011.
He has also represented the British & Irish Lions on two tours, to New Zealand in 2005 and to South Africa in 2009.
Commenting on the announcement, IRFU Chief Executive Philip Browne said: "Gordon is a wonderful servant for both Ireland and Leinster and this is proof of his undoubted talent that was indentified at a very early age.
"I am delighted that he has committed himself to playing in Ireland and is another indicator of the successful policy of keeping as many of our top players here so that they can continue to contribute to the success of both Ireland and the provincial teams."
Leinster head coach Joe Schmidt added: "Gordon is a born and bred Leinster man and since his debut in 1998 he has been a highly consistent performer for Leinster.
"His competitiveness and ability have had added huge value both on and off the field. We're delighted that Gordon will be extending his long association with his home province and I am confident that he will continue to make a positive impression both on and off the field."
Born: February 10, 1980
Debut: v Romania, October 15, 1999
Points: 35 (7 tries)
Debut: v Llanelli, September 19, 1998
Points: 299 (53 tries, 2 conversions, 4 drop goals and 6 penalties)
British & Irish Lions Career
Debut: v Argentina, May 23, 2005