The 19-year-old Netherlands international, who captained his former club in their thrilling run to the Champions League semi-finals last season, has signed a five-year deal with the Serie A champions.
"It's the news all Bianconeri fans have been waiting to hear all summer: Matthijs de Ligt is officially a Juventus player!" the club said in a statement on their website here
The contract includes a buyout clause of 150 million euros that will be activated in its third year, broadcaster Sky Italy reported on Wednesday.
De Ligt becomes one of the most expensive defenders in the world, with his national team captain Virgil van Dijk top of the list following his move to Liverpool from Southampton for 75 million pounds ($94 million) in 2018.
After breaking into the Ajax first team aged 17 in 2016, De Ligt established himself as a regular starter over the following season and soon became the most coveted defender in Europe due to his strength, anticipation and ability on the ball.
He played 90 minutes in 17 of Ajax’s 18 Champions League matches last season, scoring three times in a run which culminated in a semi-final defeat to Premier League side Tottenham Hotspur on away goals.
De Ligt did win the Eredivisie title and Dutch Cup in his final campaign at Ajax, alongside team mate Frenkie De Jong, who has since joined Barcelona.
Spanish media reported that De Ligt had also been courted by the Catalans, but the player’s agent Mino Raiola said at Juventus’ headquarters on Wednesday that the Italian club were always the preferred destination.
“It’s not a question of who wanted him most, but Juve are the best team for him. For a defender it is important to come to Italy,” Raiola told reporters.
“If you are to become the greatest in the world, it is a necessary stage.
“He’s the number one among the youngsters. He’s like (Pavel) Nedved, maybe more than him, for his mentality and he’s like Zlatan (Ibrahimovic) for his ambition. He has it all.”
De Ligt had told Netherlands’ NOS television in June that Juventus forward Cristiano Ronaldo asked him to join the Turin-based club at the end of the Nations League final after Portugal beat the Netherlands 1-0.