France's Kevin Mayer on Saturday became the first man other than the now-retired Ashton Eaton to win a global decathlon event since 2011 when he claimed gold in the world championships.
Olympic silver medallist Mayer amassed a total of 8,768 points from the 10 disciplines in the gruelling two-day event.
Germany's Rico Freimuth took silver with 8,564 while teammate Kai Kazmirek claimed bronze (8,488).
"I am so, so tired," the 25-year-old Mayer said.
"I just wanted to say you are the most amazing public in the world and I thank you for that," he said in an address to the sell-out 60,000-seater London Stadium.
Mayer clocked a third personal record of his campaign, with 13.75 seconds in the day's opening 110m hurdles.
After managing a best of 47.14 metres in the discus, the Frenchman suffered a scare in the pole vault when he needed three attempts to go over 5.10m.
That left him on 7,237 points, ahead of Freimuth (7,121) and Kazmirek (7,021) with just the javelin and 1500m remaining.
Mayer made no mistake with the javelin, throwing a best of 66.10m, before clocking a safe 4:36.73 around the strength-sapping 1500m, the final event.
On Friday, Mayer timed 10.70sec in the 100m, managed 7.52m in the long jump, threw a season's best shot put of 15.72m and registered 2.08m in the high jump before clocking a personal best of 48.26sec in the opening day's closing event, the 400m.
Two potential medal contenders crashed out in the fourth heat of Saturday's hurdles.
First, the USA's former two-time world champion Trey Hardee went down hard before Russian Ilya Shkurenyev, competing as a neutral, pulled up clutching his hamstring after the penultimate flight of barriers.