Quagliarella, who had one year left on his previous deal with the Serie A champions, has signed a contract with the Granata outfit until June 2017.
A statement from Torino read: "Torino is proud to announce it has acquired the sporting rights of Fabio Quagliarella from Juventus."
The 31-year-old Quagliarella, a product of Toro's youth system, had been strongly linked with a move away from Juve this summer after falling down the club's pecking order last season.
The former Italy international scored just one goal in 17 league appearances for the Bianconeri in the 2013-14 campaign.
Quagliarella joined Juve from Napoli in 2010 and scored 23 goals in 84 Serie A appearances for the club.
Torino were looking to strengthen their attacking line after selling star striker Ciro Immobile to Borussia Dortmund last month.
The Granata finished seventh in Serie A in the 2013-14 campaign and will play in next season's Europa League.