"My wife and I thought long and hard about it and it's something that's really going to benefit us, so that was what the move was based on. We're really happy with the decision.
"I've got one little boy that's eight months old so we took him into account and we really want him to grow up in New Zealand and be around a lot more family."
Warriors' fans have been doing celebratory backflips since Harris' signing was announced earlier this month, with the skilful and hardworking backrower set to bring a new dimension to the side's pack.
Kearney's arrival at the Warriors late last year has helped continue the club's gradual plan initiated by managing director Jim Doyle to improve and strengthen the club's culture and playing roster.
Harris will further bolster the club's Kiwi credentials, slotting in alongside test teammates Simon Mannering, Issac Luke, Shaun Johnson, Kieran Foran and captain Roger Tuivasa-Sheck.
He is confident the Warriors are headed in the right direction and is looking forward to helping the club in their quest for consistency and success, but remains reluctant to look too far into the future.
"That's what they want to do and they've got people in place to do it," he said.
"I know the type of person Mooks [Kearney] is and I know the type of culture that he wants because of the type of person he is.
"They're looking really good for the future but I'm not really thinking about that at the moment. Because of the change of environment, change of club and different people it's always going to be a new and exciting challenge but it's one that, now that the decision's been made, I've sort of put it to one side and am able to focus on this year.
"That's a huge benefit from having made this decision this early. I just want to worry about this year."
I pretty much grew up here at the Storm and it's going to be hard leaving. I'll miss the players. They're not just good players, they're good people.
It's not often Storm coach Craig Bellamy loses a grip on one of his best players and Harris's teammates are still reeling from the news of his pending departure.
Fellow forward, friend and Kiwis teammate Jesse Bromwich's disappointment was clear as he described his shock at Harris' decision, which together with the off season exit of three other senior players signals a changing of the guard at Melbourne.
"I was a bit surprised," said Bromwich. "I saw him as someone who was going to be here long-term.
"The club had already lost enough with Marika [Koroibete], Blake [Green] and Kevin [Proctor] leaving, now with 'T' going back home to the Warriors. But it is what it is.
"It definitely feels like it [a changing of the guard].
"Probably more for me, because they're all my close mates.
"I've played with them for a long time.
"It does feel a bit funny, these guys leaving. It will feel funny playing against them this year but that's business these days."
Melbourne's long reign of success is rightfully attributed to the near peerless coaching of Bellamy and the contribution and influence of Kangaroos and Queensland trio, captain Cameron Smith, halfback Cooper Cronk and fullback Billy Slater, but the contribution of the quiet and unassuming Harris cannot be downplayed.
"He's just very reliable," said Bromwich. "He hasn't missed many games, plays 80 minutes, he's very skilled, and does a lot of things that go unnoticed.
"He doesn't get the raps he deserves because of the players that we have in our team.
"He'll be good for the Warriors. It's a sad loss for us but good luck to him. I hope he goes well but not too good."
It was late last year when Bellamy first learned that Harris was considering flying the coop.
While Harris says his long-time mentor did not reveal too much other than obvious and understandable disappointment, Bellamy is reasonably philosophical about the situation and insists he was not overly surprised.
"First I heard anything were a few rumours during the [Four Nations] tour," said Bellamy.
"But the first time I realised they were pretty serious was when Tohu actually told me he was going.
"Those things happen. Tohu's done what he thinks is right for his family and whatever so at the end of the day it's done now so we're moving on.
"I'm surprised by a lot of things in the game. You go to work each day and two or three things will happen that surprise you."
Having been with the club since he was 17, Harris admits it will be tough leaving behind his Storm family and it's the quality of his friends and teammates that he'll miss.
"I pretty much grew up here at the Storm and it's going to be hard leaving some of the players that I've played every year with.
"I'll miss the players and the people they are.
"They're not just good players, they're good people, and we're all really close friends off the field and that was the hardest thing about leaving the club. That's something that I'll really miss."
Tohu Harris
Age: 25
Born: Hastings
Club: Melbourne Storm (2013-)
Height: 1.95m
Weight: 112kg
Position: Second-row
Rep honours: 16 tests for New Zealand (2013-16)
Junior club: Tamatea Rugby and Sports Club
NRL debut: Melbourne Storm v St George Illawarra, AAMI Park, 10/3/13 (Round 1)
