The Old Lady needed a win against mid-table outfit Sampdoria to ensure they could not be caught in the title race.
Closest rivals Inter Milan kept the pressure on with a 3-0 victory over Genoa on Saturday, but their challenge was ended as Juve earned a 2-0 win.
Ronaldo put his side in front in first-half injury time with his 31st goal of the campaign.
The soon-to-be-departed Miralem Pjanic fired a free-kick across the face of the box for Ronaldo, who had angled his run to meet the cross before striking the ball low into the bottom corner.
Sampdoria then had two glorious opportunities to equalise after the break, as Lorenzo Tonelli could only head wide before Gaston Ramirez’s header was straight at Wojciech Szczesny.
Juventus went on to capitalise shortly after to tighten their grip on the Scudetto trophy.
With just over 20 minutes remaining on the clock, Ronaldo cut inside and unleashed a shot at goal.
Sampdoria keeper Emil Audero was equal to it, but Juve sub Federico Bernardeschi reacted quickest to the loose ball to poke it home and double his side’s advantage.
Juve’s night was then made slightly easier as the visitors were reduced to 10 men.
Morten Thorsby was given his marching orders after receiving a second yellow card for a late foul on Pjanic.
Alex Sandro was then brought down in the area by Fabio Depaoli to win Juventus a spot kick, but Ronaldo could only smashed the penalty off the crossbar.
It mattered little though – save for Ronaldo’s Capocannoniere ambitions – as Juventus’ 35th title win was confirmed minutes later when the final whistle was blown.
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