An Adelaide product, Troisi has been overseas for his entire senior career. He began at England’s Newcastle United where he played in the reserves and was on the fringes of the first team before a move to Turkey came up.
He plied his trade at Gençlerbirligi, before catching the eye of Kayserispor after banging in a hat-trick against them playing for Gençler. Troisi moved to Italy's Serie A with his registration rights being shared by Atalanta and Juventus. He lined up for Atalanta in the 2012-13 season.