The 32-year-old inside centre has spent his entire career with Leinster, making more than 200 appearances for his home province having made his debut in 1998.
D'Arcy is one of 18 players to sign a new contract, with Leo Auva'a, Isaac Boss, Fionn Carr, Andrew Conway, John Cooney, Leo Cullen, Aaron Dundon, Mark Flanagan, David Kearney, Brendan Macken, Ian Madigan, Kevin McLaughlin, Isa Nacewa, Eoin Reddan, Rhys Ruddock, Thomas Sexton and Heinke van der Merwe all committing.
D'Arcy helped Ireland win the Triple Crown with Ireland in 2004 and is now the second-most capped centre in Irish history behind 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 RBS Six Nations Championship and Grand Slam in 2009.
Leinster coach Joe Schmidt is delighted D'Arcy has extended his stay with the club, stating his 'competitiveness and ability' add huge value to the side.
"Gordon is a born and bred Leinster man and since his debut in 1998 he has been a highly consistent performer for Leinster," commented Schmidt.
"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."
IRFU chief executive Philip Browne added: "Gordon is a wonderful servant for both Ireland and Leinster and this is proof of his undoubted talent that was identified 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."
Ireland international McLaughlin has signed a three-year deal, while Auva'a, Boss, Conway, Dundon, Kearney, Madigan, Reddan and Ruddock have extended their stays by two seasons.
In-form Nacewa has been handed a one-year extension to his contract, with new 12-month deals for Carr, Cooney, Cullen, Macken and van der Merwe.
Flanagan and Sexton have been rewarded with development deals for the 2012/13 season.