This time four years ago, Luke's reputation was at it's lowest point. In a match against England in the 2011 Tri-Nations, he tried to break an opponent's leg; and not just any player, but his cousin Rangi Chase.
It was a horrible incident, and worse when he admitted his intent after the game, saying that he "saw red" before the act. Those comments - and the sickening nature of the incident - attracted global media attention.
It wasn't a good time for the Kiwis, or Luke.
"I reacted to that and shouldn't have reacted," says Luke of the episode, prompted by Chase's defection to England. "I should have moved on with my job, I had a job on the field."
Luke took a two match ban into the off season, and also had the words of Kearney ringing in his ear.
"Really, if I look back now, that is where the transition started, from being a little shit to where I am now. I got a heads up from Mooks (Kearney), he told me how it was and where I stood. I always respect that he did that [and] from then on it's been going alright."
Kearney has been a "massive" influence, along with Rabbitohs coach Michael Maguire. For his part Kearney could see the talent but wondered if he would kick on.
"I didn't know how long he would last," said Kearney. "I've seen very talented individuals come in quick and blow out quick. In this business, sometimes it's not [just] playing ability that gets you through.
"You have to get the whole process right. He was a rough diamond and that went on for a few years."
Thankfully, Luke turned the corner - and he has been a revelation on this tour. He has - with one exception after the first test - dealt well with all the media demands, as he is one of the most popular players among the British press.
He's also usually, along with Roger Tuivasa-Sheck, the last player to leave their public training sessions; always willing to sign one more autograph, hold one more baby or smile for another selfie.
Luke didn't play well in the first test as the English forwards monstered their opposites.
But he gave a man-of the match display in London; aside from his dummy half work and defending in the middle of the ruck, his kicking in general play constantly turned the English around.
Now there is one more hurdle, one more test match in Wigan, before Luke can put his feet up for a few weeks.
He has a family trip with his wife and children, before returning to Auckland for the next great challenge - making some history with the Warriors.
Kiwi test records
Ruben Wiki 55 1994-2008
Stacey Jones 46 1995-2006
Gary Freeman 46 1986-1995
Stephen Kearney 45 1993-2004
Simon Mannering 41 2006-2015
Nigel Vagana 38 1998-2006
Issac Luke 36 2008-2015