Allegri arrives to replace Sergio Conceicao, who was sacked on Thursday evening.
It's understood Allegri has signed a two-year contract with Milan to 2027 with the option for another year. He returns to Milan after 11 years, having won the Scudetto once in his previous spell in charge.
“AC Milan is pleased to announce that Massimiliano Allegri has been appointed as the Head Coach of the Men’s First Team,” the Rossoneri said in a statement on Friday.
“Born in Livorno on 11 August 1967, Massimiliano Allegri played in Serie A for Pisa, Pescara, Cagliari, Perugia, and Napoli before beginning his coaching career in 2002. He managed Aglianese, SPAL, Grosseto, and Sassuolo before making his Serie A coaching debut with Cagliari in 2008.
"In 2010, he joined AC Milan, winning the Club’s 18th Scudetto in his first season, followed by the Italian Super Cup in 2011. From 2014 to 2019, and again from 2021 to 2024, he was in charge of Juventus, leading them to 5 Serie A titles, 5 Coppa Italia trophies, and 2 Italian Super Cups.
“The Club extends a warm welcome and best wishes to Massimiliano and his staff.”