The much-travelled 59-year-old with trademark glasses and prominent chin has signed a two-year contract to coach Juve, the Italian Serie A club said in a statement.
Twice European champions Juve, Italy's best supported club and most successful domestically, endured a horror season and could only finish seventh in the league in one of their worst top-flight performances.
A large rebuilding job is needed after Ciro Ferrara was sacked in January and interim coach Alberto Zaccheroni failed to shore up a leaking defence or re-energise a lacklustre attack.
Former AS Roma and Atalanta boss Del Neri guided Sampdoria to fourth spot in Serie A, good enough for a place in the Champions League qualifiers.
Despite helping the club reach Europe's top competition for only the second time, Del Neri decided to quit on Monday and joins former Samp sporting director Beppe Marotta at Juve.
OWN STADIUM
New Juventus president Andrea Agnelli, nephew of revered former owner Gianni Agnelli, has also been installed to restore the famous name to the hierarchy of the club and rekindle the kind of success the Turin side used to enjoy.
Juve were demoted in a matchfixing scandal in 2006 but bounced straight back to Serie A and registered impressive third and second place finishes before the last season went sour.
Expensive Brazilian signings Felipe Melo and Diego flopped badly in midfield and the new management team's first job will be to change the current squad and find top-class players willing to play in the Europa League qualifying round next term.
The decision of Del Neri and Marotta to leave flying Samp for floundering Juve is an example of the power the Juventus brand still holds in Italy despite their problems.
A new ground will be completed on the site of the old detested Stadio delle Alpi for 2011, making Juve the first Italian team to own their own stadium and gain extra revenue. Juventus had long been linked with Liverpool coach Rafael Benitez and the choice of Del Neri has prompted mixed reactions from Juve fans, especially given he famously left Porto in 2004 before managing a competitive game.
Over in Genoa, bewildered Samp fans are wondering how they lost their coach and sporting director in their finest hour.
No replacement for Del Neri has been named and supporters fear Juve's new boss will try to take their top players such as Giampaolo Pazzini with him.
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