But goals from Casemiro, Ronaldo's second and substitute Marco Asensio rewarded an outstanding second-half effort from Real.
And it made him this season's Champions League top scorer with 12.
"Zidane can stay at Real Madrid for the rest of his life", he said. "Today is a truly historic day for Real Madrid, for all Madrid fans". It was a balanced game, the first half Juventus played well but the second half we were impressive.
His impact was not lost on Juventus manager Max Allegri, who highlighted the role Ronaldo played in Real's victory amid his frustration at falling short of what would have been a treble for the Italian club.
The goal was also his 600th of all time. An intricate passing move ended with a quick one-two between Cristiano Ronaldo and Daniel Carvajal which the former finished off with panache as he ghosted into the Juventus box to coolly slot in Madrid's first of the night on the 20th minute mark.
Juventus leaked three goals in 12 games en route to the final, twice shutting out Barcelona's feared attack in the quarterfinals before blunting a free-scoring Monaco strike force in the semifinals.
But the hometown favorite finally entered the game in the 77th minute at the Millennium Stadium, getting a standing ovation from the crowd.
But, the Old Lady responded some seven minutes later, when their star striker Mario Mandzukic scored one of the greatest goals in Champions League history, with an overhead kick, which flew over the keeper, Keylor Navas.
The ball did not touch the ground between leaving Bonucci's boot and hitting the net.
Zinedine Zidane has confirmed he will remain in charge of Real Madrid after overseeing a successful defence of their European crown.
Ronaldo added his second goal in the 64th minute to give his team a comfortable 3-1 lead.
Substitute Juan Cuadrado's late dismissal, picking up a second yellow card for a late foul on Ramos (who arguably embellished the contact) was the final ounce of fight from a beaten Juve side.
Asensio tucked in the fourth goal after Marcelo had charged to the byline and Real's dominance was complete. "Me and my team mates have done the double". The numbers don't lie.
"I'm very happy. It was an incredible season again. This is one of the best moments of my career - I have the chance to say this every year", he said. It is hard to say [how long], but we need to enjoy what we are doing and we will see.