Matheson's deal will hold an average annual value of $6 million starting next season.
The 31-year-old recorded a secondary assist during the team's win over Vegas, bringing his season totals to four goals and 11 assists through 23 games this season.
Matheson spent the first five years (2015-2019) of his career with the Florida Panthers after the team selected him 23rd overall in the 2012 NHL Draft.
He would go on to join the Pittsburgh Penguins for two years (2020-2021) before eventually landing in his home province of Quebec when he joined Montreal in 2022.
Through 650 games, Matheson has posted 78 goals and 202 assists.