The 29-year-old centre back has joined the Serie A side on an initial loan, with Juve having the option to make the move permanent next summer.
They'll pay £3.22 million for the loan, rising by another £9 million should he play in 25 or more games this season.
Juventus will then have the option to take him permanently for an additional 3.5 million euros.
Höwedes' injury prone past has seen him considered something of a risky buy for Juventus as they look to replace Leonardo Bonucci, who moved to AC Milan earlier this summer.
However, his quality is un-disputable, having been a starter in the Germany side that beat Argentina to win the 2014 World Cup.
It'll be an emotional move for Höwedes, who has spent the entirety of his career so far at Schalke. He captained the side for six years, making over two hundred appearances for the Bundesliga club.
Former captain gone
Things have gone a little sour for him in previous months, as new coach Tedesco opted to strip Höwedes of the captaincy and hand it to goalkeeper Ralf Fahrmann, in a move that came as a surprise to much of Germany.
Höwedes, although not particularly keen to leave Schalke at the start of the summer, was understood to be aware of the interest of some of Europe's top clubs, with the ball really beginning to roll after he lost the captaincy.
He'll now be hoping to make his mark both domestically and in Europe for Juventus, who have been paired with Barcelona in the Champions League group stages.