MacKinnon attended the University of British Columbia where she played ice hockey for the UBC Thunderbirds.
[2] During the 2023–24, in her final season, she served as team captain and recorded ten goals and 12 assists in 26 games.
[3] She finished her career as the team's all-time leader in points by a defenceman with 34 goals and 47 assists in 126 games.
[4][5] After going undrafted in the PWHL Draft, MacKinnon was invited to the Toronto Sceptres' training camp.
[6][7] In Toronto's final pre-season game against the New York Sirens, she had a team-high 23:04 of ice time and recorded an assist.