Montreal Canadiens

Galchenyuk made the Canadiens roster for the 2012–13 season opener, a 2–1 loss to the Toronto Maple Leafs on January 19, 2013.^[7] He was the youngest player to play a full season with the Canadiens since 1984.^[8] He scored his first NHL goal on January 22, 2013, against Scott Clemmensen of the Florida Panthers, tipping-in a shot from Brandon Prust; rookie teammate Brendan Gallagher also recorded his first NHL point, an assist.^[9] Galchenyuk finished the season playing in all 48 games with 9 goals, 18 assists for 27 points and a plus-minus rating of +14, playing primarily on the left wing of the third line.^[10][11] He finished in the top ten in all three offensive categories among rookies, and was sixth overall in rookie points scoring, helping propel a resurgent Canadiens team to the second-best record in the Eastern Conference.^[12]

During the 2013–14 season, Galchenyuk missed six weeks due to a broken hand.^[13] He finished the season with 13 goals and 31 points in 65 games.

Galchenyuk scored his first career hat-trick on December 16, 2014, against the Carolina Hurricanes.^[14] The 2014–15 season also marked Galchenyuk's first 20-goal campaign, as he tallied that amount in 80 games.

On July 30, 2015, Galchenyuk (as a restricted free agent) signed a two-year, $5.6 million contract extension with the Canadiens.^[15] The following season, Galchenyuk tied captain Max Pacioretty with 30 goals to lead the team. Galchenyuk finished second in team scoring (behind Pacioretty) with 56 points.

On July 5, 2017, Galchenyuk signed a three-year, $14.7 million contract extension with the Canadiens.^[16] In the following 2017–18 campaign, Galchenyuk produced 51 points in his sixth season with the Canadiens.

Arizona Coyotes

On June 15, 2018, Galchenyuk was traded by the Canadiens to the Arizona Coyotes in exchange for Max Domi.^[17]

In his first season as a member of the Coyotes, Galchenyuk played in 72 games, with 19 goals and 22 assists.

Pittsburgh Penguins

On June 29, 2019, Galchenyuk was traded to the Pittsburgh Penguins along with Pierre-Olivier Joseph in exchange for Phil Kessel, Dane Birks, and a fourth-round pick in 2021.^[18] He suffered a lower-body injury early in the 2019–20 season and was placed on injured reserve on October 9, 2019.^[19] Galchenyuk returned to make 45 appearances with the Penguins, struggling to match his previous career offensive output in recording 5 goals and 17 points.

Minnesota Wild

On February 10, 2020, Galchenyuk, prospect Calen Addison, and Pittsburgh's first round pick in the 2020 NHL Entry Draft were traded to the Minnesota Wild in exchange for Jason Zucker.^[20]

Ottawa Senators

On October 28, 2020, Galchenyuk signed as a free agent to join his fifth NHL club in the Ottawa Senators on a one-year, $1.05 million contract.^[21] Galchenyuk began the pandemic delayed 2020–21 season, on the Senators roster as a healthy scratch. Drawing into the lineup, Galchenyuk scored on his debut with the Senators in a 4–3 overtime defeat to the Winnipeg Jets on January 19, 2021.^[22] He was scoreless in his following 7 games, featuring in just 8 of the Senators opening 15 games.

Toronto Maple Leafs

On February 13, 2021, Galchenyuk, along with Cédric Paquette, were traded by the Senators to the Carolina Hurricanes in exchange for Ryan Dzingel.^[23] On the following day, Galchenyuk was placed on waivers by the Hurricanes and upon clearing was assigned for the first time in his career to the AHL joining affiliate, the Chicago Wolves, on February 15, 2021.^[24] That same day, before he could join the Wolves, Galchenyuk was traded by the Hurricanes to the Toronto Maple Leafs in exchange for Yegor Korshkov and David Warsofsky.^[25]

The Galchenyuk acquisition was initially seen as an insignificant depth move, and after the trade he originally played for the team's AHL affiliate, the Toronto Marlies.^[26] After putting up 8 points in 6 games, Galchenyuk was called up to the Maple Leafs, eventually making his debut on March 19 on a line alongside William Nylander and John Tavares.^[27] He spent the rest of the season in the NHL, impressing fans and team staff to the extent that Maple Leafs general manager Kyle Dubas admitted to reporters that Galchenyuk's surprising success led the Maple Leafs to adjust their plans for the season's trade deadline.^[28][29] He finished the season with 12 points in 26 games played with the Maple Leafs, helping the team win their division. In the playoffs, Galchenyuk recorded four points in six games, but the Leafs were ultimately defeated in the first round by Galchenyuk's former team, the Montreal Canadiens.

Return to Arizona

On September 21, 2021, Galchenyuk was signed to a professional tryout contract with the Coyotes, making his return to Arizona after being traded by the franchise in the 2019 off-season. On October 5, Galchenyuk was signed to a one-year, $750,000 contract with the Coyotes.^[30] In the 2021–22 season, Galchenyuk played in a top-nine forward role for the rebuilding Coyotes, registering 6 goals and 15 assists to finish seventh amongst forward scoring with 21 points through 60 regular season games.

Colorado Avalanche

As a free agent at the conclusion of his contract with the Coyotes, Galchenyuk remained un-signed over the summer and for the second consecutive year accepted a professional tryout invitation to join the Stanley Cup winning, Colorado Avalanche training camp on September 20, 2022.^[31] Galchenyuk remained with the Avalanche through training camp before he was injured in his debut pre-season game, resulting in his release from his tryout on September 29.^[32][33]

In recovering from his injury and remaining within the Avalanche organization, Galchenyuk was signed to a AHL contract to begin his 2022–23 season with affiliate, the Colorado Eagles, on November 10, 2022.^[34] In recording 7 points through 7 games with the Eagles, Galchenyuk was then signed to a one-year, two-way $750,000 contract with the Avalanche for the remainder of the season on November 28, 2022.^[35][36] In joining the Avalanche, Galchenyuk made his debut on the road the following day in a 5-0 shutout defeat to the Winnipeg Jets.^[37] After going scoreless through four games with the Avalanche, Galchenyuk was placed on waivers and returned to the Eagles upon clearing on December 6, 2022.^[38][39]

Third tenure with Arizona, arrest

On June 24, 2023, the Avalanche traded Galchenyuk - a pending unrestricted free agent - to the Nashville Predators in exchange for Ryan Johansen.^[40] The Predators did not sign Galchenyuk, making him an unrestricted free agent. On July 1, 2023, he signed a one-year, two-way contract to return to the Coyotes organization.^[41]

On July 13, Galchenyuk was placed on unconditional waivers by the Coyotes for the purpose of terminating his contract. The team refused to further comment on the matter, and an investigation was conducted by the National Hockey League Players' Association. It was later revealed that Galchenyuk had been arrested on July 9 on multiple charges.^[42] On July 18, Galchenyuk announced he would enter the NHL/NHLPA player assistance program.^[43]

SKA Saint Petersburg

With NHL interest ceased as a free agent, Galchenyuk opted to pursue his professional career abroad by agreeing to a two-year contract with SKA Saint Petersburg of the KHL on August 25, 2023.^[44]