Kammala wannan jumla: Harrison ya rubuta ta Toronto Maple Leafs a zagaye na uku, 82nd overall, na
2001 NHL shigar da daftarin aiki. Bayan ya kwashe shekaru hudu a gasar Hockey ta Amurka (AHL) tare da kungiyar gona ta Toronto, Harrison ya fara buga wasan NHL a ranar 27 ga Janairu, 2006, a kan Montreal Canadiens, inda ya yi rajistar maki na farko na NHL, yana zuwa a matsayin taimako. A ranar 16 ga Yuni, 2008, Harrison ya sanya hannu kan kwangilar shekara guda tare da EV Zug na Swiss National League A, amma a ranar 27 ga Maris, 2009, ya koma Toronto Maple Leafs, ya sanya hannu kan yarjejeniya, wanda aka tsara a $ 475,000, don buga sauran kakar 2008-09.