He is the first New Zealand international to sign a contract beyond the 2027 Rugby World Cup, and may well have an eye on the British & Irish Lions tour in 2029.
New Zealand lost the 2023 World Cup final in Paris to old foes South Africa, where Barrett won the last of his 57 caps, leaving several All Blacks with unfinished business.
"I’m very proud of the way the All Blacks went at the last World Cup but there is still a burning desire to go one better at the next one," Barrett said in a media release from NZR.
"And I’m enjoying the way things are going in Wellington with the Hurricanes. I can’t wait to get into a new World Cup cycle and be really energised by it."
Barrett’s older brothers Beauden and Scott are also current New Zealand internationals.
Their father Kevin moved the family to Ireland in 2000 when he played for Athlone and worked on a farm and Jordie will return there to take up a short-term contract with Leinster.
"It’s going to be a great place for me to develop as a rugby player in a different environment where I’ll learn so many different things," Barrett said.
"And also to have a freshen up going into another World Cup cycle and some great years ahead with the All Blacks, Hurricanes and Taranaki," added referring to his three teams.
"As a whole, I think this move is going to be really challenging, but a positive challenge.
"Heading north to different conditions, different teams, different referees – I think it will open my game up, make me see the game differently and I’ll ultimately bring the best bits back to New Zealand rugby."
