Jackson replaces Jonathan Sexton, who has a hamstring injury, in the No 10 shirt in a massive surprise, not the only one produced by under-fire coach Declan Kidney.
Luke Marshall will also make his Test debut at inside centre in place of Gordon D'Arcy, who has a foot injury.
The left wing vacancy opened by Simon Zebo's foot problem has been filled by Keith Earls, while Tom Court has been chosen to replace the suspended Cian Healy at loosehead prop and Donncha O'Callaghan comes in for the injured Mike McCarthy.
But there is no doubting that O'Gara's omission from the starting XV comes as a big surprise after serving a role as Sexton's back-up since the 2011 Rugby World Cup - Jackson's sole senior international outing came in an Irish XV against Fiji last year.
O'Gara's form this season has been less than spectacular, though, with his appearance off the bench against England and a display for Munster against the Scarlets doing little to help.
"Paddy's inclusion was a challenge given the stature of Ronan O'Gara, but I think Paddy deserves a go in this one," Kidney said.
"It was a very difficult decision to leave Ronan out, it was right up there. But that's a compliment to Paddy.
"There were always going to be five changes to the side that played against England. Luke was with us all through November and accomplished himself very well."
Team: Kearney; Gilroy, O'Driscoll, Marshall, Earls; Jackson, Murray; Court, Best, Ross, O'Callaghan, Ryan, O'Mahony, O'Brien, Heaslip (capt).
Replacements: Cronin, Kilcoyne, Fitzpatrick, Toner, Henderson, Reddan, O'Gara, Fitzgerald.
Source : http://www1.skysports.com/rugby-union/news/12506/8512050/Paddy-Jackson-beats-off-Ronan-O-Gara-for-Ireland-No-10-shirt-against-Ireland
