The 20-year-old became Manchester City's fifth new arrival of the summer on Friday night when he signed a five-year contract with the Eastlands outfit.
The City boss is also inheriting a combustible character, who twice angered former boss Jose Mourinho enough to stop him playing for Inter Milan, including appearing on TV in a shirt of rivals AC Milan.
"Balotelli is a young guy and he is a good guy," said the City chief.
"Like all the young men, sometimes his behaviour is not good. But it is wrong to say he is not a good man.
"I don't believe he will have a big problem."
Mancini is confident his most recent recruit will be an instant hit.
"In one or two years he could become one of the best players in the world," said Mancini.
"He is one of the best players of his age in Europe, and I very happy to be working with him again.
"I know Mario very well. I put him in the first team at Inter when he was 17.
"He can play right wing, main striker or second striker. He is a fantastic player and he can improve purely because he has changed countries.
"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 he will be a big hit with the City fans."