The Rossoneri are entering a new era in the wake of Stefano Pioli's exit, as the man who led them to the 2021-22 Serie A title left the club at the end of the 2023-24 campaign.
Pioli had been at the San Siro helm for almost exactly five years, leaving his successor with a tough act to follow, but the board quickly settled on Fonseca as the prime candidate for the job.
The 51-year-old's arrival was recently announced by former Milan striker Ibrahimovic, who now works for the club's owners as a senior advisor and hailed Fonseca as the "right man" to lead the Rossoneri into their new era.
"He'll be the new coach, it was a thoughtful choice. We want Milan to be able to play dominant football. We studied how he coaches, how he prepares matches," the ex-Sweden talisman told reporters.
Fonseca: 'It is an honour to manage Milan'
"After five years we needed something new. Fonseca is the right man, we believe in him so much. He's the right man. Paulo Fonseca came out and we spoke to him face to face, so you get to know him, you have a feeling. He is very ambitious, he has a great desire to work, to do well and to improve. In Milan there is a coach, not a manager.
"For us, Fonseca is the top coach, otherwise he wouldn't be the Milan coach. I can say to the fans that a new football is coming, always with respect for Pioli, a dominant, offensive football is coming, with a defensive balance."
Following Ibrahimovic's endorsement of Fonseca, Milan announced on Thursday that the Portuguese had been appointed to the hotseat on a three-year deal, to which Fonseca reacted on X: "An honour, a pride, a responsibility. Forza Milan!"
Fonseca returns to Italy with a 50% win rate from 90 games in charge of French giants Lille, overseeing 45 successes in addition to 26 draws and 19 losses, leading Les Dogues to a fourth-placed Ligue 1 finish and Champions League qualifying rounds last season.
The new Rossoneri boss has also taken charge of Porto, Braga, Shakhtar Donetsk and Roma during his managerial career and has won nine major trophies, seven of which came during his time in Ukraine.
Man United transfer plans could be impacted by Fonseca switch
Fonseca's arrival at San Siro naturally begs the question which players the 51-year-old could try to poach from Ligue 1, and such plans may have a direct impact on Manchester United.
The Red Devils are believed to be chasing Monaco midfielder Youssouf Fofana, who could apparently be available for as little as £20m this summer, as his contract runs out at the end of next season.
However, ex-Arsenal and Chelsea midfielder Cesc Fabregas recently expressed his belief that Fofana was bound for AC Milan due to his desire to work under Fonseca, potentially forcing the Red Devils to look elsewhere.
In addition, Lille are set to finally part ways with Canadian striker Jonathan David this summer, and the 24-year-old is believed to be on a three-man attacking shortlist at Old Trafford.
Milan are also rumoured to possess an interest in David, though, and the Canada international scored 26 goals under Fonseca last season, another incentive for him to snub the Red Devils and follow his former boss to San Siro.