Qatar's Mutaz Essa Barshim claimed silver, narrowly missing out on his country's first Olympic gold, while Bogdan Bondarenko of Ukraine landed bronze.
Drouin, the reigning world champion and one of three bronze medalists in the event at London 2012, jumped with a clean slate throughout the competition, only falling short of the mark at 2.40 meters having already cinched the gold, according to Reuters.
Bondarenko played a tactical game, passing on two of his first four jumps, but was ultimately unable to clear 2.38m to snatch the silver from Barshim.
Russia's Ivan Ukhov was unable to defend his Olympic title after he and other Russian athletes were barred from the Games following revelations of state-backed doping in the country.