The 24-year-old Ghanaian moved to the Juventus Stadium alongside Udinese team-mate Mauricio Isla in a co-ownership agreement last August and, after renewing the Chilean midfielder's shared status with the Friulian club for another year, it has now bought Asamoah's full registration.
A statement published on juventus.com read: "Juventus Football Club has terminated the current co-ownership agreement with Udinese Calcio concerning the registration rights of Kwadwo Asamoah.
"The sum for the termination has been set at nine million euros and will be paid by Juventus over the next three financial years. This acquisition will generate economic and financial effects starting from July 1, 2013. The contract of employment signed by the player will last until June 30, 2017.
"Furthermore, Juventus and Udinese have have renewed the co-ownership deals concerning the registration rights of Mauricio Anibal Isla and (striker) Cristian Pasquato until June 30, 2014."
Asamoah made 40 appearances in all competitions in the 2012-2013 season as Antonio Conte's Juve retained the Serie A title and reached the quarter-finals of the UEFA Champions League.
The Bianconeri also renewed a co-ownership agreement with Atalanta for midfielder James Troisi while buying the remaining half of Luca Del Papa's rights from Pescara and sending fellow striker Riccardo Maniero in the opposite direction.