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.

At year's end in March 2009, she helped the Stars win the first Clarkson Cup over the Minnesota Whitecaps in Kingston, Ontario.

[17] On January 22, 2011, Poulin recorded a hat trick, including two power-play goals as BU prevailed over Vermont in a 4–0 win.

After the 2015 Hockey East tournament, she would join Shannon Doyle and fellow Montreal resident Kayla Tutino on the All-Tournament Team.

[24] 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.

She helped lead the team back to contention ahead of the 2019 Clarkson Cup; however, Poulin missed the playoffs due to injury.

[34] 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.

[39][40] 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.

[44] At the age of sixteen, Poulin made her senior Team Canada debut during the Fall Festival in Prince George, an exhibition series against Sweden, the reigning Olympic silver medalist.

After winning a second silver medal in 2009, Poulin became the all-time leading scorer in under-18 team history, with 31 points in 17 games.

[46][47] She made her full-time debut on the Canadian senior team at the 2009 IIHF Women's World Championship in Hameenlinna, Finland, earning a silver medal.

[46] Poulin scored both goals during Team Canada's 2–0 win in the gold medal game against the United States at the 2010 Winter Olympics.

[48] At the 2010 4 Nations Cup later that year, she scored a hat trick against Finland on November 12; Canada went on to defeat the US to win the tournament.

[49][50] In a game versus Russia at the 2012 IIHF Women's World Championship, Poulin put in a three-point performance in a 14–1 victory.

In August 2012, Poulin was named the captain of the Canadian Under-22 team that competed in an exhibition series versus the United States Under-22 squad in Calgary, Alberta.

[3] Poulin's teammates dubbed her "Captain Clutch" as a result of these performances, a nickname which was widely adopted in media and fan coverage subsequently.

[54] Due to a knee injury sustained in the CWHL, Poulin withdrew from the 2019 IIHF Women's World Championship after playing less than five minutes.

In her absence, Team Canada was defeated by Finland in the semi-final, missing the gold medal game for the first time in the history of the event.

[55] At the 2021 IIHF Women's World Championship, held in a bubble in Calgary, Poulin sustained an injury blocking a shot from a Swiss player in a preliminary game.

[60] Poulin logged a career-best 17 points (6 goals and 11 assists) during the women's tournament, capping it with a two-goal performance in Canada's 3–2 victory over the United States in the gold medal game.

"[6] Later in 2022, at the 2022 IIHF Women's World Championship, Poulin captained Canada to its third major international title inside a span of twelve months.

[65][8][10] Poulin scored her 200th point with Team Canada on February 22, 2023, in Game 6 of the 2022-2023 Rivalry Series against the United States, in Laval, Quebec.