in 2008.
Montreal Stars, 2007-09 Poulin spent
2007–08 with the
Montreal Stars of the
Canadian Women's Hockey League (CWHL). She appeared in only 16 games, but led rookies in scoring with 22 goals and 21 assists. So dominant was she in half a season as a 16-year-old rookie that she finished runner up in the CWHL Most Valuable Player (MVP) vote by club captains. She was also a recipient of the
Montreal Canadiens scholarship program in January 2008. For the 2008–09 season, while attending
Dawson College, she played both with the
Dawson Blues and as an associate player with the Stars. At year's end in March 2009, she helped the Stars win the first
Clarkson Cup over the
Minnesota Whitecaps in
Kingston, Ontario. In the championship game, she assisted on a goal by
Caroline Ouellette.
Boston University Terriers, 2010-15 Poulin debuted with the
Boston University Terriers women's program during the
2010–11 season. On October 2, 2010, she scored the first goal of her NCAA career in a 5–4 loss at
North Dakota. With her third shorthanded goal of the season on October 15, she tied BU's single-season record for shorthanded tallies in just four games. She led all NCAA freshmen in goals (9) and points per game (2.00) during October 2010. In addition, she led all
Hockey East freshmen in goals, assists, and points during the month. In the first seven games of her NCAA career, she had a seven-game point-scoring streak consisting of nine goals and seven assists. On December 7 and 10, two wins over
Northeastern and
Harvard, Poulin registered three goals. In both games, she had a total of 11 shots on goal and a +2 rating. On December 10, she scored two goals and a game-high eight shots as BU prevailed by a 5–3 mark over Harvard. On January 15 and 16, 2011, Poulin recorded five points (2 goals, 3 assists) in BU's two wins over
Boston College and
Maine. Against BC, Poulin notched a power-play goal and two assists. Versus the Maine Black Bears, she registered a goal and an assist. On January 22, 2011, Poulin recorded a hat trick, including two power-play goals as BU prevailed over
Vermont in a 4–0 win. The win was the Terriers' 100th win in program history. Poulin broke BU's single-season points record with her second goal of the game and later tied the single-season goals record with her third marker. She became the first Terriers player to be honoured as Hockey East Rookie of the Year in March 2011. A fracture of the shoulder did not hold her from action for the 2011–12 season. On May 11, 2012, Terriers head coach Brian Durocher announced that the captains for the 2012–13 campaign would be Poulin and Jill Cardella. For the
2014–15 season, Poulin was appointed team captain. As captain, she would lead the team to its fourth consecutive Hockey East championship. After the 2015 Hockey East tournament, she would join
Shannon Doyle and fellow Montreal resident
Kayla Tutino on the All-Tournament Team.
Les Canadiennes de Montréal, 2015-19 Poulin returned to the CWHL in the autumn of 2015 when she was selected by the Stars in the
2015 CWHL Draft. Before the season began, the Stars announced a partnership with the NHL's Montreal Canadiens and re-branded as Les Canadiennes de Montréal. At the conclusion of the
2015–16 CWHL season, she was the inaugural winner of the
Jayna Hefford Trophy as most valuable player; she also secured the
Angela James Bowl as the league's top scorer. Poulin captained the team to the
2017 Clarkson Cup championship, scoring two goals in the final in
Ottawa, with Montreal defeating the
Calgary Inferno by a score of 3–1. She won her second CWHL MVP award at the conclusion of the 2017 season. Poulin decided not to return to Les Canadiennes after the Olympics for the run up to the
2018 Clarkson Cup. She helped lead the team back to contention ahead of the 2019 Clarkson Cup; however, Poulin missed the playoffs due to injury. She won the final MVP award in CWHL history, her third win of the award, for her 2019 performance. Poulin captained one of four teams in the
first PWHPA Dream Gap tour showcase in Toronto in September 2019, leading her team to a 2–0 record in the weekend round-robin tournament. As a member of the PWHPA, she took part in the Elite Women's Showcase at the
2020 NHL All-Star Game. She was afterwards voted as the best female hockey player in the world by NHL players, after having finished second in the vote the year before. In December 2019, she had been named among the top-4 Québecois athletes of the 2010s decade by the readers of
La Presse. Poulin was among several high-profile PWHPA members who reacted indifferently to the news of the
National Women's Hockey League's 2020 expansion into Canada with the addition of the
Toronto Six, stating that "I think there's a reason why many of us are not playing in that league." At the 2021 Secret Cup, which was the Canadian leg of the
2020–21 PWHPA Dream Gap Tour, Poulin scored the third-period game-winner for Team Bauer (Montreal) in a 4-2 championship win over Team Sonnet (Toronto). She also recorded two assists for a three-point performance. Overall, Poulin was the scoring champion in the 2021 Secret Cup, with five goals and six assists in five games. In what would prove to be the final PWHPA season in 2023–24, Poulin led the Dream Gap Tour in scoring with 12 goals and 27 points in 20 games, and help lead Team Harvey's to the 2023 Secret Cup title.
Montreal Victoire, 2023-present against the
Minnesota Frost on January 6, 2024. In 2023, the PWHPA bought out the rival
Premier Hockey Federation and launched the new
Professional Women's Hockey League (PWHL). Poulin, who was credited with an important role in pursuing a collective bargaining agreement in the new league, spoke of her desire to create "a viable professional league for the next generation, for ourselves." With each of the six new teams able to make three initial free agency signings, Poulin was widely assessed as the best player available, but it was generally assumed that she would sign with the
Montreal team.
The Athletic remarked that "it would be cool to see a bidding war between teams for Poulin," but acknowledged "we're just waiting for the Montreal signing announcement." On September 5, Poulin, along with
Laura Stacey and
Ann-Renée Desbiens, were reported as the Montreal team's first three players. In 2023, Poulin was named Montreal's
captain. PWHL Montreal finished in second in the
PWHL's inaugural regular season, but were eliminated in the first round of the playoffs by
PWHL Boston. Poulin missed three games of the regular season, but still finished tied for second in points, with 23 in 21 games played. She was named a First Team All-Star, and was a finalist for both the
Billie Jean King Most Valuable Player and the Forward of the Year award. Ahead of the
2024–25 PWHL season, all of the PWHL's franchises adopted new names, with PWHL Montreal rebranded to the Montreal Victoire. On January 29, 2025, Poulin scored the first hat trick of the season against the
Ottawa Charge. The Victoire finished first in the league in the regular season, while Poulin claimed the
PWHL Top Goal Scorer award with a league-leading 19 goals in 30 games (and 26 points total). She later received the Billie Jean King Most Valuable Player honour, the league's Forward of the Year award, and her second First Team All-Star designation. The Victoire faced the Charge in the semi-finals of the playoffs, and were ousted in four games. Poulin, described as "devasted" at the team's failure to reach the final for a second year, said "we're going to need to look in the mirror and see what we can do differently, how we can change and how we can get better." During the
2025 PWHL Expansion Draft, held due to the introduction of the league's
Seattle and
Vancouver clubs, Poulin was one of three players protected by Montreal. On October 23, 2025, she signed a two-year contract extension with the Victoire. Poulin scored her first goal following the return from the injury she sustained at the 2026 Olympic Games on March 3, 2026, scoring the shootout winner in a 4-3 victory over the
Toronto Sceptres, which extended Montreal's winning streak to 6 games. ==International play==