"Jonathan David is officially a Juventus player. The Canadian striker has signed a five-year contract until June 30, 2030," the Serie A club said.
David scored 109 goals in 232 matches during his five-year spell with Ligue 1 Lille.
He shone for Lille on the European stage last season, scoring the only goal in the 1-0 win over Real Madrid, and a double in the 3-1 win over Real's city rivals Atletico.
With a reputation as a trusty striker, he finished fourth in Ligue 1's scoring charts last term, second the season before and third in 2022/23.
David is the first new face since Frenchman Damien Comolli took over as Juve's general manager last month.
David, who helped Lille to be crowned French champions in 2021, joins a club that has won just a single trophy, last year's Italian Cup, since 2021, and that finished a disappointing fourth in Serie A last season.
Their coach Thiago Motta was sacked in March after only eight months in the post.
Juve, currently managed by Igor Tudor, are reportedly in the hunt to sign Victor Osimhen, the Nigerian whom David replaced at Lille.
Osimhen was loaned out by Italian champions Napoli to Turkish side Galatasaray last season. They have placed a 70-million-euro (£60.41 million) price tag on the player.
Local media suggest Juve are also looking at Manchester United's England international Jadon Sancho.