Having skipped the Six Nations earlier this year to focus on his preparations for the Paris Games, Dupont starred through France's campaign.
And he was equally as influential in Saturday's gold medal match as France overcame two-time defending champions Fiji 28-7, with Dupont scoring twice and setting up another try.
It marked France's first gold of their home Games.
"It is sensational. It is unbelievable. It is a big reward for us," said Dupont, who was introduced as a half-time substitute with the scores tied at 7-7 at the Stade de France.
"It is huge. We worked a lot for a lot of months and a lot of years – in some players' case – for this moment."
Dupont teed up Aaron Grandidier within 21 seconds of his introduction, before twice going over himself.
Grandidier was born in London but elected to represent France.
"I found out France had a system that allowed you a bit more time to break out on to the scene, so I was like, 'you know what, screw it, I've got nothing to lose, this is what I want to do'," he told BBC Sport.
"So I decided to chase it and pursue that dream."
Fiji had never previously before lost an Olympic match, while they conceded 20 points in a game for the first time.
Dupont, voted the 2021 World Player of the Year, missed out on this year's Six Nations to prepare himself for the sevens at the Games.
And he scored a brilliant solo try in the dying seconds at a jam-packed Stade de France to wrap up a 26-14 triumph over Argentina on Thursday.
Aaron Grandidier had earlier crossed the line twice along with back-rower Andy Timo's opener in a dominant first half, though Argentina fought back after the break.
Rodrigo Isgro responded for Los Pumas before Marcos Moneta sneaked over after France were reduced to six when Jordan Sepho was sin-binned.
Yet home favourite Dupont stepped up in the decisive moment, whipping the crowd into frenzy after setting up a last-four meeting against South Africa, who overcame New Zealand in the quarter-finals.
South Africa finished third in Pool A as New Zealand topped the group, but the Springboks exacted revenge against the All Blacks to secure a semi-final berth.
The Springboks raced into a two-try lead before holding out for a 14-7 victory to stun one of the pre-tournament favourites.
Fiji, champions in 2016 when the event was first introduced and four years later in Tokyo, unexpectedly found themselves up against it as Chay Mullins bundled over twice to snatch a 10-7 lead for Ireland at half-time.
Zac Ward extended the Irish lead but two tries in less than 30 seconds from Selestino Ravutaumada and Terio Tamani snatched a 19-15 turnaround.
The two-time Olympic champions will meet Australia after the Wallabies downed the United States with ease.
Corey Toole and James Turner both crossed in the first half en route to a convincing 18-0 triumph in the final match of the day, sending Australia into their first rugby sevens semi-final at the Olympics.
