Castonguay spent her early childhood living in the
Pointe-Claire municipality of the
urban agglomeration of Montreal. Her parents divorced when she was young and her father moved to the
Outremont borough of
Montreal, where she began playing youth hockey with boys. Her play ultimately earned a scholarship to study at
Niagara University and play with the
Niagara Purple Eagles women's ice hockey program. During her
college ice hockey career (2005 to 2009), she typically played on the third-line and amassed a total of 23 points across 121
NCAA games. Though she was not a star player on the team, she was recognized as a leader in the room and served as team
captain in her final two seasons. She obtained a bachelor's degree in finance from the university, and earned National Scholar Athlete honours during her time there. After graduating with her undergraduate degree, she enrolled at l'
Université de Montréal Faculty of Law and earned
Juris Doctor in 2012. During her time as a law student, she interned with
Montreal Canadiens general manager
Pierre Gauthier. ==Career==