New boss Maurizio Sarri was absent from the dugout as he is recovering from pneumonia, but he would have been buoyed by a performance that suggested his side will once again be the team to beat this season.
Giorgio Chiellini scored the only goal of the game after 21 minutes, before Ronaldo saw his strike ruled out for offside before the interval.
Juve was unable to add a second despite dominating throughout, although it mattered little as it comfortably kept Parma at arm's length to start the season in familiar fashion.
The visitors started with a spring in their step and should have gone ahead after 12 minutes, Ronaldo's header from 10 yards fizzing narrowly over.
Wojciech Szczesny pawed away Roberto Inglese's instinctive effort at the other end before Chiellini opened the scoring, the veteran defender diverting home Alex Sandro's scuffed volley from 10 yards.
Ronaldo should have doubled their advantage eight minutes later but flashed wide after being played in by Gonzalo Higuain.
There was more frustration for the Portugal international before the break when he saw a goal disallowed by VAR for offside. He lashed home superbly from a tight angle but replays showed he was marginally offside as he raced to collect Douglas Costa's pass.
Parma started the second half with more intent than it had shown in the opening 45 minutes, but struggled to breakdown Juve's resolute defence.
Ronaldo clipped over from Costa's pull-back on the hour mark before Parma goalkeeper Luigi Sepe kept out the former Real Madrid's star's powerful drive from 20 yards.
The Bianconeri eased up in the closing stages, rarely looking like they would add a second, but the damage had been done by their defensive colossus in the first half.
Juve welcomes last season's runner-up and Sarri's former club Napoli to Allianz Stadium next Sunday (AEST), while Parma travels to Udinese a day later.