Portugal forward Rafael Leao, whose dip in form coincided with AC Milan's struggles in recent seasons, joined Galatasaray Sunday, the Istanbul club announced.
The four-time reigning Turkish champions, who have qualified for the Champions League, said they had paid 38 million euros ($44mn) for the 27-year-old attacker, who was also being courted by Aston Villa.
Galatasaray said he signed a four-year contract worth 10 million euros a year.
The Portuguese international had been welcomed by a crowd of supporters when he arrived in Istanbul Saturday.
About "20% of the profit made on the player's next transfer will be paid to AC Milan," the Turkish club added in its statement.
The Sporting Lisbon academy graduate will play alongside Nigerian Victor Osimhen, the Turks' star striker and former Bayern Munich winger Leroy Sane.
After arriving for a club-record 49.5 million euros from Lille in 2019, Leao scored 80 goals in 291 games for Milan.
He was a key figure in their 2021-22 Serie A triumph, but concerns over his commitment and declining production clouded the end of his time at the club.
Earlier this summer, Milan broke their club record when they paid 74 million euros to acquire another Portuguese attacker, Goncalo Ramos, from Paris Saint-Grrmain.
"It's a tough moment saying goodbye to my teammates after seven years," Leao said Friday after watching Milan beat visiting Venezia 2-0.