PSG has now claimed the prestigious trophy on 14 different times.
The Parisian giants needed a stoppage-time leveler followed by a successful spot-kick decider to get past their arch-rivals in Kuwait and capture a fourth straight Trophee des Champions victory.
The European champions seemed to be sailing towards a comfortable win in the showdown between the Ligue 1 winners and the French Cup holders after the French winger found the scoring early on.
However, Marseille struck two times in the closing moments to seize a surprise advantage. First, Mason Greenwood scored from the spot-kick, before the defender inadvertently turned the ball into his own net for an own-goal.
In a breathtaking turn of fortune, Goncalo Ramos grabbed a vital equaliser in the final seconds to force the match into a penalty shootout. PSG goalkeeper Lucas Chevalier then stood as the hero, saving decisive kicks from O'Riley and Traore.
In the shootout, Goncalo Ramos, Vitinha, the full-back, and Desire Doue all converted with composure for PSG to complete a 4-1 penalty victory.
Now 14-time champions PSG, who met last season's Ligue 1 runners-up Marseille after achieving a league and cup double, have now won this competition for the 12th time in the last 13 years.
