Conte has signed a two-year contract, the Turin-based club said in a statement.
Juve, who finished seventh in Serie A for a second successive season, sacked Luigi Delneri last season after just one term in charge and have turned to the Siena coach having been linked with the 41-year-old in the past.
"We want to succeed and we want to do it with Antonio Conte. He is the first piece in the jigsaw to return to winning ways," club president Andrea Agnelli told reporters.
Conte, who led Siena to promotion back to Serie A this month, was at the centre of one of the best midfields in Europe in the 1990s and early 2000s as Juve routinely dominated Serie A and reached the latter stages of the Champions League.
He won 14 trophies as a player with the club known as the "Old Lady."
Since then Juve, Italy's best supported and most successful club domestically, have endured a dreadful spell on and off the field.
Their 2006 demotion for match-fixing was followed by an immediate return to the top flight under Didier Deschamps and ta third-place Serie A finish under Claudio Ranieri but both managers surprisingly left.
In 2009/10, both Ciro Ferrara and Alberto Zaccheroni failed to stop a sudden rot and they ended up a lowly seventh.
NEW STADIUM
Delneri was brought in, having guided Sampdoria to fourth, but Juve again flopped having struggled in the transfer market, failing to recruit the very top talent as they used to do with the stigma of match-fixing still haunting the club.
Juve, trying to boost revenues, move to a new stadium for next season on the site of their old Stadio Delle Alpi having shared with Torino the cramped Stadio Olimpico since 2006.
They will become the first Italian club to own their own ground but difficulties finding a sponsor for the new stadium have again undermined their attempt at renaissance and chief executive Jean-Claude Blanc recently announced his departure.
Fiery Conte brought Bari up to Serie A two years ago but then left after a row with the board before a short unhappy spell at Atalanta, who have been linked with a move for former boss Delneri now they are back in the top flight.
"His CV speaks for itself," Juve goalkeeper Gianluigi Buffon said of Conte from Italy's training camp.
"He is an extremely charismatic and positive person, he knows the environment perfectly. He knows Juve better than me and is intelligent and informed."
