Cut from his local AAA squad as a youth, Matt Martin worked his way back through AA and junior C before earning a spot as a walk-on with the Sarnia Sting, where he skated on a line with Steven Stamkos and later served as team captain. Growing up in Windsor, Ontario, he developed a physical, straightforward approach that carried him through junior hockey.
Selected 148th overall by the New York Islanders in the 2008 draft, Martin turned professional in 2009 and played in Bridgeport before making his NHL debut in February 2010, picking up two assists in that first game. He signed a three-year entry-level deal with the Islanders in September 2009 and netted his first NHL goal on October 29, 2010 against Alex Auld and the Montreal Canadiens.
Martin established himself as a hard-checking winger in New York. He agreed to a four-year contract with the Islanders on September 15, 2012, and set a single-season NHL hits mark with 382 checks in 2014–15. The next season his trio with Casey Cizikas and Cal Clutterbuck earned praise as one of the league's top fourth lines. As an unrestricted free agent on July 1, 2016, he signed a four-year, $10 million contract with the Toronto Maple Leafs and settled into a protective, fourth-line role in Toronto.
His time with the Maple Leafs included playoff action—he posted two points in game two of the series against Washington—but also a slump that saw him a healthy scratch for 18 straight games in early 2018; he finished that regular season with 12 points in 50 games and was nominated for the King Clancy Memorial Trophy on April 23, 2018. Toronto traded him back to the Islanders on July 3, 2018 for goalie Eamon McAdam. That autumn he missed time with an upper-body injury and was placed on injured reserve on November 15, returning to play November 26. On January 11, 2021, he signed a four-year, $6 million extension with New York. He remained with the Islanders, signed a one-year deal on October 26, 2024, appeared in 32 regular-season games for 2 assists, and on June 24, 2025 announced his retirement and moved into the Islanders front office as a special assistant to GM Mathieu Darche.
Martin's game has always revolved around physicality: heavy hits, standing up for teammates and providing energy in a depth forward role. Off the ice, he started the Matt Martin Foundation in 2015, was recognized for community work, and is married to Sydney Esiason with four children.