Scott had his first-place finish confirmed on Sunday, but had to wait until the conclusion of the event on Tuesday.
The 29-year-old did not even need to finish the medal race, but still crossed the line behind USA's Caleb Paine in second.
Britain's Mills and Clark finally clinch 470 sailing gold
The Weymouth-based sailor won three of 11 races in the competition, and will now join up with Sir Ben Ainslie in his 2017 America's Cup team.
Scott hands GB their 17th gold of the Games, and the sailor follows in the footsteps of four-time Olympic gold medallist Ainslie.
Netherlands' Bouwmeester wins Laser Radial gold
Thompson must wait to fight for medal after Laser-class race postponed by a day