The Olympic silver medallist won gold in the world decathlon on Sunday scored a total of 8,768 points from the 10 disciplines in the two-day event.
Germany's Rico Freimuth took silver with 8,564 while his teammate Kai Kazmirek claimed bronze with 8,488 points.
“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 has been in tremendous form clocking 10.70sec in the 100m, managing 7.52m in the long jump, throwing a season’s best shot put of 15.72m, clearing 2.08m in the high jump and setting a personal best of 48.26sec in 400m on Friday.
He led the opening day with 4478 points.
On Saturday, Mayer registered his third personal record of the event, with 13.75 seconds in the 110m hurdles. After managing a best of 47.14 metres in the discus throw, the Frenchman cleared 5.10m in the third attempt.
Mayer kept his composure in the javelin throw with a best of 66.10m, before clocking a safe 4:36.73 around the 1500m which was the final event.
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.
- with AFP