"(That change) probably came at the start of last year after the Rangi Chase incident. It didn't just affect me. It affected everyone around me. I saw it as a wake-up call, a kick up the arse. Ever since then I have been on a happy road. I have been happy with how I am going."
So have many others. On Thursday, he was named Hooker of the Year at the Rugby League International Federation awards, beating off the not-inconsiderable challenge of Cameron Smith, and up until last weekend's semifinal with England was arguably the player of the tournament.
He had a quieter game against England but his effectiveness was thwarted by the fact the English forward pack dominated the game. It's an area the Kiwis will need to assert themselves in if they are to have any chance of beating Australia in tomorrow morning's final at Old Trafford.
Before they kick off, Luke will lead New Zealand's new haka, Te Iwi Kiwi. It was created in time for the tournament and is expected to become the haka for all New Zealand league teams in the future.
It acknowledges the fact New Zealand teams are made up of players from various origins - the present Kiwis have players of Maori, Pakeha, Samoan, Tongan and Laotian decent - but they all come together for a common purpose.
A cultural adviser worked in collaboration with Luke, Thomas Leuluai and Elijah Taylor. Luke comes from a kapa haka background and, although not fluent in Maori, he knows enough to offer input.
This year is also the first time he has led the haka on his own, where previously he did it with Adam Blair.
"I have taken it upon myself to play a bigger part and be the leader of the haka," he says. "Someone has to take it on and I love leading it.
"I have always wanted to be a senior player. This weekend's game will be my 29th test and I'm something of a veteran. Everyone has dreams of one day captaining their country and hopefully I do that one day."
Kiwis utility Alex Glenn has seen the change in Luke since Glenn made his Kiwis debut in 2011. Glenn is a more natural leader and the pair were part of the emerging leaders' group established earlier this year.
"When I first met him, he was very shy," he says. "He was one of those people who didn't speak up and kept to himself. He knew what he wanted to say but couldn't really get it out to the boys and they used to laugh at him. Now, especially in this camp, the boys have really respected what he's said. He takes that confidence on to the field and, from what I've seen, he's playing his best footy."
Smith, too, thinks Luke is.
"He's a great player," the Australian captain says. "He's probably had the best season of his career.
"He's a lot different to most dummy halves who play the game these days. Most try to pass the footy or create an option for one of their runners. He's a guy who loves tucking the footy under his wing and he's powerful and quick. If you give him an opportunity to run, he will take it every time."
Interestingly, Smith has been doing more running than Luke in this World Cup. He's had more carries (113 to Luke's 93) and dummy-half runs (93 to 73) whereas Luke has made more metres (635m to Smith's 464m) and tackle breaks (19 to 5) and produced considerably more offloads (9 to 1).
They are polar opposites both in personality and style of play but equally crucial to their side's success tomorrow.
"I am a massive fan of Cameron Smith," Luke says. "Everyone tries to model their game around him. I have different attributes. His power is his control he has over his game. Hopefully one day I can get there.
"I am chipping away at every little thing I can add to my game. Not be exactly like him but to be able to control a game. He's the ultimate player in my position at the moment. I know he worked really hard on his game and I am just trying to do the same."
Cameron Smith
• Age: 30
• Height: 1.83m
• Weight: 90kg
• Tests: 36 (2006 debut)
World Cup stats
• Tries: 1
• Metres: 464m
• Carries: 113
• Dummy-half runs: 93
• Average carry: 4.11m
• Tackle breaks: 5
• Offloads: 1
Issac Luke
• Age: 26
• Height: 1.74m
• Weight: 84kg
• Tests: 28 (2008 debut)
World Cup stats
• Tries: 1
• Metres: 653m
• Carries: 93
• Dummy-half runs: 73
• Average carry: 6.83m
• Tackle breaks: 19
• Offloads: 9