The team announced the deal Friday. Terms were not available.
The 34-year-old had 12 goals and 14 assists in 59 games last season. Darche added a goal and an assist in seven playoff games.
Canadiens general manager Pierre Gauthier said in a statement: "Mathieu is a classy veteran player who displays great leadership and determination, and we strongly believe he can help us achieve our goals in the upcoming season."
Darche has 25 goals and 35 assists in 189 career games with Montreal, Columbus, Nashville, San Jose and Tampa Bay.