Born on October 20, 1992, in Milan, Mattia De Sciglio first played in Serie A in the 2011–12 season. He spent six years as an AC Milan player and made 110 league appearances, making him the youngest defender to do so in Serie A. He also made 13 Coppa Italia appearances and 10 Champions League appearances. During those years, he regularly displayed his talent on the right flank and picked up two Italian Super Cups (in 2011 and 2016).

De Sciglio led all defenders in assists and crosses that were completed (15) in his final season with the Rossoneri.