[3] On July 9, 2015, Juulsen agreed to terms on a three-year, entry- level contract with the Canadiens.

[6] On March 2, Juulsen scored his first career NHL goal during a 6-3 win over the New York Islanders.

On February 1, 2019, the Canadiens announced Juulsen was out indefinitely with a vision-related issue following twin puck strikes to the face during the November 19, 2018 match against the Washington Capitals.

[9] Prior to the commencement of the 2021–22 season, on October 10, 2021, Juulsen was traded by the Panthers to the Vancouver Canucks, along with Juho Lammikko, in exchange for Olli Juolevi.

[10] Juulsen competed with Team Canada Pacific to win a silver medal at the 2014 World U-17 Hockey Challenge.