"He has shown tremendous progress this season with his consistency and attitude. Together with David he gives us so much value at both ends of the field and has plenty of improvement in him."
Maumalo, who made his Kiwi Test debut in Denver in June, plays his 22nd NRL match of the season – and the 63rd of his career – when the Warriors face Canberra in their final regular season match at Mount Smart Stadium on Friday night.
"I'm so grateful to my family and to everyone at the club for the way they've supported me throughout my career so far," said Maumalo.
"I feel a lot better about playing in the NRL now. I'm more relaxed and I am enjoying my footy. That's the most important thing."
Together with Fusitu'a and Tuivasa-Sheck, Maumalo has formed a potent back three which has contributed significantly to the Warriors claiming a finals berth for the first time since 2011.
Maumalo and his centre partner on the left edge Solomone Kata have provided 16 tries to the Warriors' cause so far this season.
Warriors general manager football Brian Smith said securing Maumalo was another vital signing for the club's future plans.
"Ken is yet another wonderful young player who has come through our system," he said.
"The coaching staff have worked hard to develop Ken into a valued first grader and he has responded. He's having a terrific season and richly deserves the security this long-term contract gives him."