Samuela Fainu said coach Benji Marshall's emphasis on family helped convince him to stay with the Wests Tigers.
"The club has looked after me, my family, and my brothers very well,'' Samuela said.
"I love playing alongside these boys, so to get to do it for two more years makes me very excited about what's to come.
"Benji Marshall values family and, for me, that's one of the most important things in my life.
"He not only wants me to be the best footy player I can be, but he also wants me to be the best version of myself off the field, and that's something that you can't find in many places.
"Within the group, we have achieved so much already. You can see the changes we've made, and I truly feel we are building towards something very special here.
The Tigers have confirmed Fainu will remain at the club for another two years. Code Sports reported earlier this week that negotiations were advanced on a deal worth around $800,000 a season, with ratchet clauses eventually lifting the value beyond $1 million.
Fainu has recommitted alongside his brother Sione. The club is also keen to extend half Latu, with hopes he will follow soon.
Fainu would have attracted competition if he had reached free agency.