It's a significant boost for the Warriors because Leuluai has become, in the space of less than two years, a vital element of their mix.
There had been speculation — largely driven from England — that the 31-test Kiwi was pondering a move back to Super League where he enjoyed so much success with Wigan.
His partner is English, and a return would have been a way for Leuluai to prolong his career in a less physically demanding competition.
His re-signing is crucial for coach Andrew McFadden, as Leuluai has been one of the main drivers of the cultural change at the club. He's the ultimate professional, both in his hard-nosed approach to training and in the focused 80 minutes he gives to each game.
Leuluai knows what it takes to win games and sets a good example for the rest of the squad.
The 28-year-old is one of the best defenders in the NRL and has an underrated attacking game. He's a strong, direct runner with an accurate kicking game and a clever pass.
His retention is also vital for Sam Tomkins, as the duo have an uncommon bond.
"Once you play with someone for a while, you get used to it," Tomkins said earlier this year. "[Thomas] knows my game inside out and has added more to my game than any other player. He was a big factor in me coming here."
Leuluai has also been a strong influence on Shaun Johnson, and the two halves usually room together on away trips.
After playing every minute of every game last season, Leuluai starts just his seventh match of the season, against Cronulla today.
