The 22-year-old Rhinos academy product moved to Auckland at the end of last year, but has secured a release from the final two seasons of his contract for personal reasons.
He will rejoin Rhinos in pre-season on a deal until the end of 2029.
The second-rower’s return is more good news for Rhinos, the day after a 34-6 win at second-placed Warrington Wolves lifted them two points clear at the top of Super League.
Gannon is Leeds’ first signing for next year and will effectively replace James McDonnell, who is heading to NRL newcomers Perth Bears at the end of this season.
He made his Rhinos debut in April, 2021 and featured 73 times before rejecting a contract offer midway through last year in order to test himself in the southern hemisphere’s elite competition.
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Leeds Rhinos confirm Morgan Gannon return
Rhinos’ sporting director Ian Blease said: “We are delighted to be bringing Morgan back home to the Rhinos.
“We were clear when he left that we had worked hard to persuade him to stay at AMT Headingley and we are looking forward to having him back in 2027.
“I would like to thank the New Zealand Warriors for the way they have handled the situation and I am sure Morgan will return having developed even more from his time with the Warriors.”
Rhinos coach Brad Arthur hailed Gannon as “an outstanding young man who has shown a great deal of maturity already in his young career”.
He said: “The fact he is one of our own – having come through our development pathway – and knows our club makes this a perfect fit for all of us.
“I know Morgan will be keen to pick up where he left off when he starts pre-season with us and it will be good to have him back around the boys.”
Gannon added: “I am looking forward to being back at the Rhinos in 2027.
“I am grateful for the opportunity I have had with the Warriors this year and I am looking forward to helping the squad for the remainder of this season.
“I know the Rhinos are going well this season and I wish them all the best for the rest of this campaign.”
