The 29-year-old will remain with his hometown club until at least the end of the 2024 campaign.
Having joined from Wigan St Patricks ARLFC at the age of 16, Powell has gone on to become one of the key figures in the Leadership Team.
“I’m honoured and delighted to be staying at this great club for at least another two years," he said.
"The club has been everything to me and my family and I couldn’t imagine playing anywhere else.”
Since his debut in 2012, Powell has made 243 appearances for Wigan, scoring 39 tries.
So far in 2022, he has played 13 games, scoring two tries.
Executive director Kris Radlinski said: “Sam is a strong leader at the club. He is a cultural architect who demands high standards every day.
"He has tremendous humility and, even though he didn't play in the Challenge Cup final, his presence on the training field and around the team that week was pivotal to our success.
"He possesses the DNA we would want every Wigan Warriors player to have.”
Powell has won one World Club Challenge, two Super League Grand Finals and two League Leaders’ Shields.
“Sam guides the team on and off the field and has the competitive spirit that every great Wigan player has," said head coach Matt Peet.
"He is determined to make his next few years his best ones and we would expect nothing less from him.”