Martin was part of one of the most effective fourth lines in the NHL last season, with Cal Clutterbuck and Casey Cizikas, scoring 10 goals and an NHL career high 19 points with a plus-2 rating in 80 games.
Maple Leafs general manager Lou Lamoriello said Martin stood out as the type of fourth-line player who can help Toronto improve.
"Certainly his size and strength, and we feel his skating is very good," Lamoriello said. "I've had the good experience to play against him for a good number of years to where I came from (New Jersey Devils), so I've seen him over a period of time, and our staff liked him and our coaching staff liked him, and that's the most important thing."
Martin, a native of Windsor, Ontario, will get to play in front of his hometown crowd and for coach Mike Babcock.
"Honestly, it really factored into my decision, I think," Martin said. "He's appealing as a coach. He's been so successful throughout the years with the [Detroit] Red Wings. I've watched players emerge, you know, Justin Abdelkader, under his style; Leo Komarov last season obviously had a big year. It's appealing to me in that sense. I think he's someone that can bring your game to another level, and I think that's what we all want as players."
Martin has 42 goals and 88 points in 438 NHL games. Many consider him to be nothing more than an enforcer brought in to protect the Maple Leafs' young core of players, including forward Auston Matthews, the No. 1 pick in the 2016 NHL Draft. Martin has led the NHL in hits in each of the past five seasons, including 365 in 2015-16.