The 31-year-old Leinster great – capped 88 times since making his Test debut in 2009 – has made a remarkable comeback since coming close to retiring in 2015 due to a neck injury.
He has accrued an impressive array of winners’ medals in his time, being part of three Six Nations title-winning sides with Ireland – including the Grand Slam last year – and four European Cup triumphs with Leinster.
Healy, who is tied to Ireland till the end of the 2020/21 campaign, said the support he had received from Leinster and Ireland during the rough days with his injuries was a major factor in signing on again.
“There have been some difficult times over the last few years for me personally with injury,” said Healy in a statement issued by the IRFU.
“But the support within the Leinster and the Irish rugby family was very humbling from fellow players, coaches and supporters and it’s something that I won’t forget.
“It made this decision all the easier knowing that I was part of something bigger than just a rugby team.”
David Nucifora, the IRFU performance director, said Healy – who is on course to appear at a third World Cup later this year – was an example to many in the way he had persisted in carrying on playing.
“He has bounced back from adversity to return to the top of the international and club game,” said Nucifora.
“He will continue to be a leading performer for Ireland and Leinster over the coming years.”