The biggest transfer of the summer was officially completed on Tuesday afternoon as the two European heavyweights reached an agreement on a deal worth a rumoured £105m.
Ronaldo bows out of the Spanish capital as Los Blancos' all-time top scorer, registering 450 goals in 438 matches to help secure four Champions League crowns and two La Liga titles.
Explaining his decision to leave in an open letter to Madrid fans, the Portugal international insisted that the time feels right to move on following close to a decade with the club.
"These years in Real Madrid, and in this city of Madrid, have been possibly the happiest of my life," he said. "I only have feelings of enormous gratitude for this club, for this hobby and for this city. I can only thank all of them for the love and affection I have received.
"However, I believe that the time has come to open a new stage in my life and that is why I have asked the club to accept transferring me. I feel that way and I ask everyone, and especially our followers, to please understand me.
"They have been absolutely wonderful for nine years. They have been nine unique years. It has been an exciting time for me, full of consideration but also hard because Real Madrid is of a very high demand, but I know very well that I will never forget that I have enjoyed football here in a unique way."
Juve are believed to have agreed to pay the five-time Ballon d'Or winner wages of £500,000 a week.
Ronaldo's statement in full, published on Madrid's official website, can be viewed here.