Early career As a youth, Hainsey played in the 1995
Quebec International Pee-Wee Hockey Tournament with a
minor ice hockey team from
Springfield, Massachusetts. Hainsey was drafted in the first round, 13th overall, by the
Montreal Canadiens in the
2000 NHL entry draft, from the
University of Massachusetts Lowell (1999-2001) of the
Hockey East NCAA conference. He began his professional career with Montreal's
American Hockey League (AHL) affiliates, the
Quebec Citadelles and
Hamilton Bulldogs, and played in the Calder Cup finals against the
Houston Aeros, which the Bulldogs lost. Hainsey made his NHL debut for the Canadiens on October 11, 2002, versus the
New York Rangers in New York.
Columbus Blue Jackets After spending three seasons with the Canadiens organization, Hainsey was claimed off
waivers on November 29, 2005, by the
Columbus Blue Jackets, He recorded 6 goals and 33 assists in his first season in Atlanta. He would go on to record 45 points in the next two seasons with the Thrashers. After their relocation to
Winnipeg,
Manitoba, to become the
Winnipeg Jets to start the
2011–12 season, Hainsey recorded 10 assists in 56 games. He was a key part of the negotiating team for the
National Hockey League Players' Association (NHLPA) in the lockout. On January 6, 2013, an agreement was reached to end the lockout. He finished the
2012–13 season with no goals and 13 points in 47 games with the Jets.
Carolina Hurricanes On September 12, 2013, Hainsey signed a one-year, $2 million contract with the
Carolina Hurricanes after the team announced that defenseman
Joni Pitkänen would miss the season due to injury. Hainsey was named an
alternate captain of the Hurricanes during the
2015–16 season. He marked his 200th NHL assist against the
Pittsburgh Penguins on January 20, 2017.
Pittsburgh Penguins On February 23, 2017, Hainsey, in the final year of his contract, was traded to the Pittsburgh Penguins in exchange for a second-round pick in the
2017 NHL entry draft and
Danny Kristo. It was with the Penguins that on April 12, 2017, after 907 career NHL games and surpassing
Olli Jokinen's previous playoff games drought "record", Hainsey made his
Stanley Cup playoff debut, doing so against the Columbus Blue Jackets.
Toronto Maple Leafs An unrestricted free agent following the season, Hainsey signed a two-year, $6 million contract with the
Toronto Maple Leafs on July 1, 2017. He was signed to replace the departing
Matt Hunwick, who coincidentally signed with the Penguins that same day. On November 1, 2018, Hainsey played in his
1,000 career NHL game.
Ottawa Senators On July 1, 2019, Hainsey signed a one-year, $3.5 million contract with the
Ottawa Senators. For the
2019–20 season, Hainsey was named an alternate captain for the Senators. On December 10, 2019, Hainsey played in his 1,100th game, playing against the team which drafted him, the Montreal Canadiens in Montreal. On December 19, 2019, it was announced that Hainsey suffered a knee injury in the 5–4 overtime victory over the Nashville Predators. He missed seven games before returning to the ice on January 9, 2020. On April 1, 2021, Hainsey announced his retirement from the NHL. ==Career statistics==