The Dutch ace - a long-time leader - confirmed his place at the top of the podium with victory in the medal race, finishing ahead of Nick Dempsey of Great Britain in silver position and Poland's Przemyslaw Miarczynski, who took bronze.
Julien Bontemps of France finished the medal race in second behind Van Rijsselberge, but it was not enough to secure him a place on the podium.
He finished fifth overall, behind Toni Wilhelm of Germany, who just missed out in fourth.
Van Rijsselberge came into the medal race with gold mathematically assured, knowing he only had to turn up and compete - even if he finished last - to clinch the victory.
The fight was on for silver and bronze, though, with Dempsey holding the advantage after the 10 opening fleet races.
He boasted an 11-point cushion over nearest rival Wilhelm, with Miarczynski a further six points back.
Van Rijsselberge set the tone from the off and rounded the first mark in front, ahead of Bontemps.
The Dutchman went on to secure medal race victory ahead of the Frenchman to cap a gold medal-winning regatta in style in what was the last men's RS:X race at the Olympic Games, with the sport due to be replaced by Kiteboarding for Rio 2016.