Gareth Bale – playing in his hometown of Cardiff – and new signing James Rodriguez had been the poster boys in the build-up to this fixture, but Ronaldo made sure he claimed the headlines with two goals in the Welsh capital.
Champions League winners Real were in control throughout against the Europa League victors, but had to wait until the half-hour mark to open the scoring.
Bale found Ronaldo with a wonderful cross from the left, teeing up the Portuguese for a relatively simple sliding finish.
Ronaldo made sure of Real's second Super Cup triumph four minutes after the interval with a powerful left-footed strike.
The match-winner's performance saw him take his tally of goals against Sevilla to 18 since his arrival in Madrid in 2009.
Rodriguez and fellow new arrival Toni Kroos made their competitive debuts in an attacking Real XI and Sevilla – without Alberto Moreno amid reports the full-back is set to join Liverpool – had to withstand considerable pressure in the opening stages.
Ronaldo saw a free-kick deflected onto the roof of the net 13 minutes in, while Real's menacing forward line almost delivered the goods five minutes later.
Rodriguez whipped the ball into the penalty area after darting down the left wing, but Bale's finish was blocked by Denis Suarez, with replays suggesting the possible use of an arm by the Sevilla man.
Despite playing the role of spectator for 20 minutes, Iker Casillas had to be alert to keep out a Vitolo effort at his near post, before opposite number Beto denied Ronaldo from point-blank range at the other end.
It was Ronaldo who broke the deadlock soon after, sliding in to guide home a sensational Bale cross from deep.
Real continued to dominate possession for the remainder of the first half, but failed to carve out clear-cut opportunities to double their advantage.
However, they wasted no time in going two up after the break.
Ronaldo pulled the trigger from just inside the box after receiving possession from Karim Benzema, sending the ball hurtling past Beto and into the back of the net.
Rodriguez drew a superb one-handed save from Beto in the 70th minute, before Carlo Ancelotti brought the Colombian's debut to an end with the introduction of Isco three minutes later.
Sevilla made a concerted late effort to reduce the deficit - Grzegorz Krychowiak seeing a shot from the edge of the area saved by Casillas before Diogo Figueiras fired just wide.
Yet the result was never in doubt as Real deservedly added the 2014 UEFA Super Cup to their trophy cabinet, and Bale almost provided a fairytale finish when bringing a save from Beto with the last action of the game.
