Amateur career Growing up, Leivo played with the Barrie Colts U18 AAA team before being drafted by the
Sudbury Wolves of the
Ontario Hockey League (OHL). He was selected in the 11th round after scoring 30 goals with the minor midget team. Leivo immediately joined the team and made an impact on their play. He tallied his first career OHL goal on October 7, 2010, in a 4–3 loss to the
Niagara IceDogs. By early February, Leivo and fellow team rookie Sam Scutt moved into the top 25 in OHL rookie scoring after accumulating 17 points. Later that month, Leivo served a two-game suspension for a late instigator penalty during a game. In his first regular-season with the Wolves, Leivo accumulated 13 goals and 17 assists for 30 points through 64 games. Leivo was subsequently selected 86th overall by the
Toronto Maple Leafs in the
2011 NHL entry draft. Following the NHL entry draft, Leivo participated in the Maple Leafs Rookie Camp but was returned to the Wolves for their
2011–12 season. However, due to an injury at the camp, Leivo made his season debut on October 5, 2011, against the
Sault Ste. Marie Greyhounds. Once Leivo became a mainstay in the lineup, he greatly improved on his rookie season scoring. By December 20, 2011, Leivo ranked second in team scoring with 11 goals through 29 games and was tied for 7th place in the league in game winning goals. Leivo finished the regular-season with 32 goals and 41 assists and added two goals and one assist in the playoffs. during the
2012–13 season Leivo returned to the Wolves for the
2012–13 season as one of their alternative captains alongside defensemen Justin Sefton and Charlie Dodero. He began the season strong and earned the OHL Player of The Week honour for the week ending October 7 after scoring six goals in three games with a plus-minus rating of plus-5. He finished the month of October by earning the Wolves' Three-Star Award after scoring 10 goals and six assists, including two winners, for 16 points through 16 games. Leivo continued to improve offensively as the season continued and finished his Sudbury Wolves tenure with 147 points through 164 career games. On January 8, 2013, Leivo was traded in a multi-player deal to the
Kitchener Rangers alongside
Frank Corrado, Joel Vienneau, and various draft picks. Upon joining the Rangers, Leivo scored 10 goals and 19 assists through 29 regular season games. Once the season concluded, he signed an Amateur Tryout contract with the Toronto Marlies on April 16, 2013.
Professional career Toronto Maple Leafs organization in 2013 Leivo played four games with the Marlies, tallying two assists, before the conclusion of the 2012–13 season. He was invited to the Maple Leafs 2013 Prospects Camp where he earned praise from Jim Hughes, the Leaf's Director of Player Development. Hughes stated that Leivo drew comparisons to Leaf's player
Joffrey Lupul in terms of his skating abilities. In spite of his improvements, Leivo was cut from the Leaf's training camp and he began the
2013–14 in the AHL with the Marlies. However, in the early stages of the 2013–14 season, on October 10, 2013, Leivo made his NHL debut with the Toronto Maple Leafs in a 4–0 win over the
Nashville Predators. He later scored his first NHL goal, against
Cam Ward of the
Carolina Hurricanes on October 17, 2013. During the game, Leivo accidentally collided with goaltender
James Reimer causing him to miss most of the contest. He was re-assigned to the AHL on October 23 but recalled the following day in order to replace Lupul in the lineup. Leivo played seven games with the Leafs but spent the majority of the season with the Marlies. During his time in the AHL, Leivo worked under former figure skater
Barbara Underhill to improve his skating stride. Leivo finished his rookie season scoring 23 goals to become the first Marlies rookie to eclipse the 20-goal plateau in franchise history. Following his first full professional season, Leivo participated in the Leafs Development and training camp playing alongside
Nazem Kadri and
William Nylander. Due to injuries to
David Clarkson and
David Booth, Leivo was expected to start the season on a line with Kadri and Lupul. However, before the season began, the Maple Leafs claimed
Richard Pánik off waivers from the
Tampa Bay Lightning leading to Leivo being re-assigned to the Marlies to begin the
2014–15 season. He played in eight regular season games with the Marlies, collecting four points and nine penalty minutes, before being recalled to the NHL level on November 7, 2014. During the month of March, Leivo declined offensively as he tallied two goals and five points for the Marlies while his shooting percentage fell 9 per cent. Throughout his time with the Marlies, Leivo played on both left and right wings with various linemates including
Trevor Smith,
Spencer Abbott,
Greg McKegg, and
Sam Carrick. Following the AHL All-Star game, Leivo returned to the NHL lineup due to various injuries on the Maple Leaf's main roster. On February 11, 2016, Leivo suffered an upper-body injury after scoring a goal against the
Edmonton Oilers causing him to miss numerous games. After recovering, Leivo was re-assigned to the Marlies on February 29 before being recalled again on an emergency basis alongside
Frédérik Gauthier in mid-March. By March 25, Leivo had accumulated five goals through 12 games with the Maple Leafs while also collecting 14 goals and 26 assists in 45 games with the Marlies. Leivo re-joined the Marlies on March 25, Following his stellar season in the AHL, along with decent production in his few NHL appearances, Leivo was rewarded with a two-year contract on July 21, 2016. In the first year of his new contract, Leivo continued to improve on his previous season's success despite playing fewer overall games due to an injury that derailed the start of his season. After suffering an injury during training camp, Leivo went pointless in five games with the Marlies on a conditioning stint before being declared unfit to play by the Maple Leafs. After making his season debut, Leivo failed to become a mainstay in the Leafs lineup until
Mitch Marner suffered an injury in mid-February. He scored his first goal of the season in a 7–1 win over the
New York Islanders and earned a promotion from the fourth line. He was then slotted into the Leafs' home-ice shutdown line alongside
Leo Komarov and
Nazem Kadri where he began producing at a rapid rate. However, his health declined in March which disrupted the remainder of his season. Leivo finished the 2016–17 season with 10 points through 13 games. Leivo began the
2017–18 season trying to crack the Leaf's lineup out of training camp for the third straight season. His agent Ian Pulver stated that Leivo wished to stay in Toronto and fight for time on ice rather than take a chance with
free agency. However, by February, Leivo had only played in 12 games for the Maple Leafs and as NHL’s trade deadline approached,
Nick Kypreos reported that he had requested a trade, citing his lack of use by the team as the primary reason. In spite of this, Leivo was not traded, waived, or earning more playing time in the three weeks following the request. When asked about the request,
General manager Lou Lamoriello denied that such a request had been made.
Vancouver Canucks After appearing in a career-high 27 games for the Leafs during the
2018–19 season, Leivo was traded to the
Vancouver Canucks in exchange for
Michael Carcone on December 3, 2018. By December, Leivo had accumulated seven goals and 19 points through 36 games before suffering a fractured kneecap. Although he was originally expected to only miss two to three months, Leivo was eventually declared unfit for the remainder of the season.
Calgary Flames and Carolina Hurricanes As a free agent from the Canucks after parts of two seasons with the club, Leivo opted to remain in
Western Canada by signing a one-year, $875,000 contract with the Calgary Flames on October 24, 2020. He stated that one of the reasons he signed with the Flames was due to his familiarity with numerous players on the team, specifically
Sean Monahan,
Mark Giordano,
Jacob Markström, and
Christopher Tanev. Upon joining the team, Monahan described Leivo as "a skilled player, big guy, skates well and thinks the game at a high level." In the Flames home opener against his former team, the Canucks, Leivo played on their top line alongside Monahan and
Johnny Gaudreau. As his production dipped, Leivo was dropped to a different line but eventually re-joined Gaudreau and Monahan in early March. Although he had not yet scored his first goal with the team, Leivo was eighth on the team with 2.27 expected goals due to his 24 shots and 27 individual scoring chances. Upon rejoining the Flames' top line, Leivo scored his first goal with the team on March 4, 2021, in a 7–3 win over the
Ottawa Senators. Following this game, the Flames fired coach
Geoff Ward and replaced him with
Darryl Sutter. Under this new coach, Leivo was dropped to the fourth line but scored their only two goals of a 2–1 win over the
Montreal Canadiens in Sutter's first game. His rising success stagnated in late-April when he missed seven games while isolating for two weeks after testing positive for COVID-19. Prior to his removal from the NHL's COVID protocol list, the Flames were eliminated from playoff contention. After concluding the
2020–21 season with six goals and three assists through 38 games, Leivo signed a one-year, $750,000 contract with the
Carolina Hurricanes. Following their development and training camp, Leivo was waived and re-assigned to their AHL affiliate, the
Chicago Wolves. When the NHL once again paused games due to an outbreak of the coronavirus in December, Leivo was assigned to the Chicago Wolves. During his time with the Wolves in December, Leivo accumulated a league-leading 14 points through six games to help Chicago post its first perfect record for a month in its franchise history. As such, he was named the AHL's Player of the Month for December and subsequently became Chicago's sixth player in team history to earn the AHL’s Player of the Month honour. In April, Leivo was suspended one game as a consequence of spearing during a game against the
Texas Stars. As the season continued, Leivo and teammates
Stefan Noesen and
Andrew Poturalski played a vital role in helping the team qualify for the
2022 Calder Cup playoffs. During the post-season, Leivo led all AHL skaters with 20 points through 13 games to help the Wolves advance to the Calder Cup Finals. As the Wolves beat the
Springfield Thunderbirds in the Finals, Leivo won the
Jack A. Butterfield Trophy as the Most Valuable Player of the Calder Cup Playoffs.
St. Louis Blues After a successful season within the Hurricanes organization, Levio as a free agent was signed to a one-year, $750,000 contract with the
St. Louis Blues on July 14, 2022. Leivo made the Blues opening night roster out of training camp to begin the
2022–23 season. He appeared in 51 regular season games with the Blues in a depth role, posting 4 goals and 12 assists for 16 points.
Salavat Yulaev Ufa As a free agent from the Blues, Leivo halted his North American career by signing abroad for the first time after agreeing to a one-year contract with Russian club
Salavat Yulaev Ufa of the KHL on September 15, 2023. In April 2024, Leivo signed a one-year extension with Salavat Yulaev. In December 2024 and January 2025 Leivo became the first KHL player to record four hat tricks within a 30-day period, scoring three against
Amur Khabarovsk on December 25, three against
Barys Astana on December 30, three against
HC Neftekhimik Nizhnekamsk on January 15 and finally scoring three against
Avangard Omsk on January 20. Leivo was selected for the 2025
KHL All-Star Game, but could not participate because of an injury. On February 25, 2025, Leivo signed a two-year contract extension with Ufa, which was scheduled to run through the 2026-27 season. On March 22, 2025, Leivo scored his 49th goal of the
2024–25 season, setting the KHL record for most goals scored in a regular season, overtaking the 48-goal mark set by
Sergei Mozyakin in the
2016–17 season. He also scored the most points of all players in the regular season with 80. ==Personal life==