Luke, 26, will become a ten-year-plus player in the cardinal and myrtle of South Sydney, having made his first grade debut for the Rabbitohs against the Melbourne Storm in 2007.
Luke has gone on to play 153 NRL matches, all for South Sydney, scoring 354 points from 33 tries and 111 goals. He has also represented New Zealand in 29 Test matches including winning the 2008 World Cup with the Kiwis.
Rabbitohs Head Coach Michael Maguire is very happy to have the services of Luke at the Club at least until the end of 2017.
"Issac is one of the key players at our Club and I've seen him become a leader amongst men during my time with the Rabbitohs," Coach Maguire said.
"His work rate on the field is matched only by the effort he puts into his game and preparation off the field.
"He's a family man, who has taken this Club to heart and you can see that every time he performs for the team.
"He's one of those players that everyone wants to play with, and loves playing with, and that's the kind of player we want at this Club.
"Issac is one of the premium hookers in the game and I couldn't be happier that he has, again, committed long term to the Rabbitohs family."
Luke said he is excited to have extended his tenure with his one and only NRL Club.
"I absolutely love this Club, I love playing with the boys, and I love representing the Members each week," Luke said.
"Since ‘Madge' joined the Club I've played my best football and I think everyone recognises that he's brought the best out in me.
"My team mates are my brothers. This team is part of my family.
"I'm happy to be part of the history of this Club and hopefully I can play my part in building on the legacy that was created by the past players before us.
"I look at the premiership teams on the walls and I want to be up there on that wall with them, and everyone here at the Rabbitohs is working towards the one goal.
"I'm glad I have this part of my future sorted out and I can't wait to get the all clear to get back out on the field and play my part in another special season with the Rabbitohs."