Chiesa, 26, joins on a four-year deal and is Arne Slot’s first signing to arrive at the club.
The forward was a star of the Italy squad that beat England on penalties in the Euro 2020 final at Wembley.
“I’m so happy to be a Liverpool player. When Richard Hughes called me and he said, ‘do you want to join Liverpool?’ – and the coach called me – I said yes immediately because I know the history of this club, I know what it represents to the fans,” Chiesa told the club website.
“So, I’m so happy and I can’t wait to get started.”
He impressed during his debut season at Juve, being named in Serie A’s team of the year, but struggled for form after suffering a serious knee injury in January 2022 which required surgery.
Chiesa, who has been capped 51 times by Italy, scored 32 goals in 131 appearances for Juventus, including 10 in 37 matches last season.
Newly-appointed Juventus boss Thiago Motta left Chiesa out of his first two matchday squads this season, with his contact set to expire next summer.
Liverpool boss Slot previously said “it would be a surprise for all of us” if the club does not make any summer signing, adding the standards are “really high” to come into “such a good squad”.
On Tuesday, Liverpool agreed to sign Georgia goalkeeper Giorgi Mamardashvili from Valencia in a deal worth up to £29m – but he will not join until next season.