Kearney has been negotiating with the IRFU for several months and only last week expressed frustration at the length of time it was taking to reach a conclusion, especially as it impinged on his preparations for the Six Nations.
The 2009 Lion also sent a shot across the IRFU's bow by intimating that he was confident of attracting interest from French clubs. This assertion came in the same week as it was announced Jonathan Sexton had turned down the IRFU's offer.
But the IRFU have now secured his services for the next two years at least, following on from the news that Cian Healy and Mike Ross have also signed new deals.
"I'm delighted to be continuing my rugby career in Ireland," said Kearney.
"Leinster Rugby has always been my home and I am very excited to be remaining here to play with a great bunch of players and coaching staff.
"I have been very lucky to have experienced success with that same group over the last number of years, and with the great support we have, it made it a very easy decision for me."
Leinster coach Joe Schmidt would have been loath to lose Kearney, especially as he must now enter the market for an out-half in light of Sexton's imminent departure. The Kiwi expressed his delight at the successful conclusion of negotiations.
"Rob has shown his tremendous ability and genuine drive to keep progressing, so it's great that he'll be continuing with Leinster in the years to come," said Schmidt.
Meanwhile, four players have been added to the Ireland training camp for the week as cover for those nursing injuries.
Henshaw was called up as a precaution as Kearney has a bruised upper back, although team manager Mick Kearney dismissed any concerns over the full-back's availability for Sunday's game against England.
"If the game were played today or tomorrow then they wouldn't be able to play," said Kearney. "But they are taking part in modified training and we will see as the week progresses."
Ruddock has been called up as cover for Peter O'Mahony, who is being treated for concussion following a clash of heads in Saturday's win over Wales.
The Munster flanker trained yesterday and is expected to be named in the team on Friday.