At the age of 11, Ambrose moved from AA to AAA boys hockey, and in her second season she was named team captain. She began to play women's ice hockey as a 14-year-old in 2008. She competed for Ontario Blue at the 2008 National Women's Under-18 Championship and participated in all five games. Ontario Blue had a fourth-place finish at the tournament in Napanee, Ont. In 2009, she was invited for Canada's National Women's Under-18 Team. She was one of seven defenders named to the final roster, making her just the second 15-year-old to suit up for the under-18 squad. On February 19, 2012, Ambrose became the all-time scoring leader among defenders in Provincial Women's Hockey League history. She recorded a three-point game versus the Mississauga Jr. Chiefs to surpass Laura Fortino.
Hockey Canada
Ambrose was part of Canada's National Women's Under-18 Team to a gold medal at the 2010 IIHF World Women's Under-18 Championship in Chicago. As a member of the gold medal winning squad, a hockey card of her was featured in the Upper Deck 2010 World of Sports card series. In addition, she participated in the Canada Celebrates Event on June 30 in Edmonton, Alberta which recognized the Canadian Olympic and World hockey champions from the 2009–10 season. During the 2011–12 Canada women's national ice hockey team season, she was a member of the Canadian National Under 18 team that participated in a three-game series vs. the US in August 2011. In addition, she was named the team captain. She was part of the gold medal winning Team Ontario Red squad at the 2011 Canadian National Women's Under-18 Championships In the second game of the 2012 IIHF World Women's U18 Championship, Erin Ambrose earned two points in a 6–0 shutout of Germany.
NCAA
On January 16, 2012, it was announced that Ambrose committed to join the Clarkson Golden Knights women's ice hockey program in autumn 2012. Ambrose was the leading rookie scorer among all defenders in the NCAA, recording 36 points. Her 30 assists were a program record while her 1.06 points per game made her one of only three blueliners in NCAA points to average at least one point per game. To begin her sophomore season, Ambrose amassed five and four-point performances, which also included hat tricks in consecutive games. Such performances took place against the RIT Tigers and St. Lawrence Skating Saints. She would finish said season as the co-winner of ECAC Hockey's Best Defensive Defenseman Award. Serving as an assistant captain in her junior and senior seasons, the junior season would be highlighted by recording the 100th point of her career with the Golden Knights. Becoming the ninth player in program history to reach the century club, she achieved the feat on January 10, 2015, scoring a goal in a 1–1 draw versus conference rival Cornell. In her senior season, she missed the first nine games due to injury. Despite the setback, she would log 28 points, on the strength of 21 assists. The last goal of her NCAA career was scored on March 5, 2016 against the Colgate Raiders. She would also record two assists in the game for a three-point performance. In the previous game, Ambrose would record four assists, her best offensive output for the season.
After being released from Hockey Canada's Centralization camp, Ambrose was traded from the Toronto Furies to Les Canadiennes de Montreal. Taking place on December 13, 2017, the Furies received first and third round picks in the 2018 CWHL Draft, a first round pick from the 2019 CWHL Draft, plus a third round pick from the 2020 CWHL Draft. Making her debut with Les Canadiennes on December 16, she recorded a pair of assists, including an assist on the overtime winner by Kayla Tutino, a 5–4 win versus the Markham Thunder. With Les Canadiennes, Ambrose would make appear in the 2019 Clarkson Cup, challenging the Calgary Inferno. Ambrose would gain an assist in the game, a 5–2 loss to Calgary.
Career statistics
PWHL
Hockey Canada
NCAA
CWHL
Awards and honours
Directorate Award, Best Defender, 2012 IIHF World Women's U18 Championship.
