The 29-year-old forward is signed through the 2022-23 season. He could have been an unrestricted free agent after this season.
Byron had 35 points (20 goals, 15 assists) in 82 games and averaged an NHL career-high 16:08 of ice time per game last season. He was on the ice for Montreal's first day of training camp after he was expected to miss six months following shoulder surgery April 18.
"My shoulder feels incredible," Byron told the Canadiens website Sept. 14. "It's probably the best it's felt in a few years.
"It's been a long summer skating by yourself and getting ready for camp. I just got cleared last week to skate with the guys. It's exciting. It's fun. I'm happy I'm not missing a day of camp. It always [stinks] when you miss time and you're behind the eight ball. I'm back out there with everybody, and I get to battle with the guys and get ready to be at my best for Game One of the season."
