[2] After fast-tracking his high school graduation, Hanifin matriculated at Boston College as a 17-year-old, playing for the Eagles and becoming the second-youngest player in the team's history.

On July 11, 2015, Hanifin signed a three-year, entry-level contract with the Hurricanes forgoing the remainder of his college eligibility.

[8] Despite the Hurricanes not qualifying for the 2018 Stanley Cup playoffs, Hanifin ended the regular season with a career-high 10 goals and 32 points.

On June 23, 2018, Hanifin was traded to the Calgary Flames (along with teammate Elias Lindholm) in exchange for Dougie Hamilton, Micheal Ferland, and prospect Adam Fox.

[14] Growing up, he attended Saint Sebastian's School, where he played for the varsity team in the eighth grade.