After weeks of speculation, denial, offers and counter-offers, Balotelli returned to the San Siro to wear the red and black colours of the club he had supported since his childhood.
The 22-year-old made a name for himself with Milan's city rivals Inter, but having failed to live up to his early promise during two controversial years at Manchester City, he received a hero's welcome on his return to Lombardy.
At the official unveiling ceremony, Balotelli promised his football would make the headlines from now on.
He told acmilan.com: "It has always been a dream for me to play for Milan and I am happy to back near my family but I would rather play than talk about it.
"It's an honour and a great opportunity so I hope to grow as a player and I am here as a man. I hope to stay here as long as possible."
The second Milan derby of the season is just three weeks away and Balotelli will face the side who nurtured his talent for four years.
"If I score, I will celebrate," he added.
Milan vice-president Adriano Galliani presented Balotelli with his number 45 shirt before saying: "As a club we are happy to bring back our Italian player after long negotiations.
"I have to thank Manchester City in helping this transfer to go through. It was the most complicated of my career."
"We are happy that Balotelli has joined the team he supported as a boy and it has long been a dream of mine to bring the player to the club."
Balotelli is likely to feature in an attacking trident alongside Stephan El Shaarawy and M'Baye Niang, with Giampaolo Pazzini and Robinho forced to bide their time on the bench.
Midfielders Nigel De Jong and Massimo Ambrosini will play no part due to injury but recent signing Cristian Zaccardo, a World Cup-winning defender, could make his debut against the Bianconeri.
Udinese head coach Francesco Guidolin felt compelled to apologise for recent setbacks despite delivering a creditable 1-0 victory over Siena.
The Zebrette are still smarting from a 4-0 humbling at Juventus and Guidolin promised to shake things up, starting on Sunday night.
He said: "I accept the criticism but I don't let it get to me and I continue on my own path.
"In the last two and a half years we have become used to playing well in front of our own fans, but we can certainly play better. I'm focused on that.
"We need to improve the quality in our approach play in order to get more satisfying results."
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