The 28-year-old has signed a four-year deal with Massimiliano Allegri’s side, which will see him pocket €7m per season.
Higuain passed a medical in Madrid on Friday after Juventus agreed to pay the Argentine’s full release clause.
He attracted interest from Liverpool, Arsenal and Atletico Madrid but Napoli held firm on their valuation.
Advertisement
His move signifies the biggest transfer in Serie A history.
He becomes the fifth summer signing of the Serie A champions, following the acquisitions of Miralem Pjanic, Dani Alves, Medhi Benatia and Marko Pjaca.
Higuain scored a stunning 36 league goals in 2015/16, equalling the Italian record for the most in a top-flight campaign.