Neto signed a four-year deal with a buyout clause of €80m on Friday, joining his compatriot and fellow shot stopper Diego Alves at Valencia.
The Brazilian acted as reserve goalkeeper to Gianluigi Buffon during his two seasons at Juventus, but he was in goal as Massimiliano Allegri’s side beat Lazio 2-0 to lift the Coppa Italia in May.
The 27-year-old started just 10 Serie A matches in spell at Juve, who he joined from Fiorentina.
He leaves with a pair of league titles, two Coppa Italias and a Champions League runners-up medal after Juve lost to Real Madrid in Cardiff last month.
Neto’s move comes after Valencia allowed goalkeeper Mat Ryan to join Premier League newcomers Brighton and Hove Albion, while Alves has also been linked with a move away.