Simon Schempp of Germany lost out to the Frenchman in a furious sprint finish, coming in a fraction behind to take silver, while Norway's Emil Hegle Svendsen took the bronze medal.
Edged out for the gold medal in 2014, the Frenchman crossed the line and angrily slammed one of his ski poles into the snow, thinking that Schempp had beaten him, but his frustration turned to joy moments later when he was declared the winner of a thrilling race.
"Four years ago in Sochi I lost by only three centimetres, so I thought the story was repeating again. Tonight it's incredible," he told reporters.
"I've won a lot of competitions in my career and I'm very proud about it but I also had big losses, like in the world champs in 2013 against (bronze medallist Emil Hegle) Svendsen, in the Olympics in 2014 with Svendsen as well," he explained.
"Being today in the first place after a tight sprint is something you dream of as an athlete, so I am proud," Fourcade said.
Fourcade, the 12.5km pursuit champion, got off to a bad start with a miss in the first shoot and, adding insult to injury, he hit the deck just after leaving his penalty lap, costing him even more valuable seconds.
He faced stiff competition from the German trio of Schempp, Benedikt Doll and Erik Lesser, who took turns at the head of the pack with the 31-year-old from Perpignan.
Doll was in with a shout of a medal but a miss on the range sent him sliding down the field and his compatriots Schempp and Lesser were left to battle it out with Fourcade.
Shoulder to shoulder at the final shoot, Fourcade and Schempp both had a single miss, with Lesser putting himself out of contention with his first two wayward shots of the night.
Schempp stayed with Fourcade all the way on the final skiing lap but the wily Frenchman, who was runner-up in this race in 2010 and 2014, threw his ski across the line to claim the gold by the narrowest of margins and write his name in the record books.
(Reporting by Philip O'Connor; Editing by Amlan Chakraborty and Clare Fallon)
