The Italian giants have captured the former Manchester City midfielder on a five-year contract until the summer of 2029, ending long-running speculation about Luiz's future.
The 26-year-old was previously heavily linked with a move to Arsenal, who had two bids rejected in the summer of 2022 and were thought to have reignited their interest this time around too.
However, Juventus moved quickly to strike a deal with Unai Emery's side, and while a swap deal involving two players did not materialise, the two parties shook hands on a sizeable fee.
With the Bianconeri paying €50m (£42.4m) to prise Luiz away from Villa Park, the 26-year-old becomes the Lions' second-most expensive sale of all time, only behind Jack Grealish's £100m switch to Manchester City three years ago.
Luiz "really happy" to join Juventus
"It's official - Douglas Luiz is a Juventus player! The Brazil international has signed a 5-year contract until 30 June, 2029 with the Bianconeri," Juventus said in a statement.
"Now, Douglas Luiz embarks on a new adventure with Juventus after five years with Villa, where he has shown exponential growth technically, physically and tactically. Welcome to Juventus, Douglas. We can't wait to see you on the pitch!".
The midfielder himself - who is currently on duty with Brazil at the Copa America - issued a short video message to Juventus supporters, where he stated that he was "really happy" to sign for the Italian giants.
"Hello Juventini, I'm really happy to be a Bianconero and I can't wait to play in the Allianz Stadium," Luiz said. "See you soon, and Forza Juve!".
Luiz departs Aston Villa with a record of 22 goals and 24 assists from 204 matches since his arrival from Manchester City in the summer of 2019, playing a key role in the Lions' successful push for Champions League qualification last season.
What about Aston Villa's double Juventus signing?
Before settling on a £42.4m fee, Aston Villa and Juventus were initially discussing an audacious swap deal involving Luiz, Weston McKennie and Samuel Iling-Junior, but that transaction fell through.
McKennie ended up having a change of heart, but Iling-Junior is still expected to complete a move to Villa Park in a separate deal, as will Argentinian midfielder Enzo Barrenechea.
Having confirmed Luiz's switch to Juventus by the June 30 deadline, Aston Villa can record his sale on their accounts for the 2023-24 financial year in another huge boost to their Profit and Sustainability situation.
The West Midlands giants have now made four major sales in the summer window, having also seen Morgan Sanson (OGC Nice), Omari Kellyman (Chelsea) and Tim Iroegbunam (Everton) leave the club.
Meanwhile, Ian Maatsen and Lewis Dobbin have arrived from Chelsea and Everton respectively ahead of the 2024-25 Premier League season, which for Villa begins with a trip to West Ham United on August 17.