The 20-year-old has signed a five-year contract with the Premier League side.
Balotelli had long been linked with a move to link up with his former boss Roberto Mancini at Eastlands.
“I think that Mario is one of the best players of his age in Europe, and I very happy to be working with him again,” the manager told City’s official website.
“His style of play will suit the Premier League, and because he is still so young there is a big chance for him to improve.
“He is a strong and exciting player, and City fans will enjoy watching him.”
Balotelli joins City for an undisclosed fee believes to be around £24million.
