The Jamaican had struggled for form and fitness all season, stumbled his way through the semi-finals and got nowhere close to the times that his rival Justin Gatlin had been posting.
Back at the arena where he first exploded onto the world stage at the 2008 Beijing Olympics, however, Bolt surged past the in-form American over the last 30 metres and crossed the line in 9.79 seconds, his fastest run of the year.
“I came out here, relaxed, no stress and brought it home. My aim is to be number one until I retire and therefore I am pushing myself and pushing myself,” said the 29-year-old after striking his trademark “Lighting Bolt” pose.
“It is all about running the race and getting it done. You can call that race rusty. I could have run faster. This title means a lot to me. It has been a long season with me coming back from injury.”
Gatlin finished second in 9.80 to take silver as he did at the world championships in Moscow two years ago, while young guns Andre de Grasse of Canada and American Trayvon Bromell finished together in third place in a time of 9.92.
They will both be awarded bronze medals after running identical times down to a 1000th of a second.
“I am speechless, all I can say is wow!” said de Grasse, whose time was a personal best.
American Mike Rodgers was fifth in 9.94 while Tyson Gay, Asafa Powell and Jimmy Vicaut were sixth, seventh and eighth in 10 seconds dead.
Su Bingtian, who received the loudest cheers at the start of the race as the first Chinese to reach the final of the blue riband sprint at a global championships, finished last in 10.06.
The victory for Bolt will be an undoubted boost for a sport which has spent three weeks locked in a public relations crisis over allegations of widespread doping among athletes.
With Gatlin, who has twice served bans for the use of banned substances, being one of four convicted dopers in the final, a victory for Bolt proved to be more significant than who was the best sprinter.
“I understand why (people thought it was important for me to win),” Bolt added. “But as I said, I wanted to do it for myself. It was a big deal.”
Bolt, the reigning Olympic champion and world record holder, has now not been beaten in the 100m or 200m in six major global championships going back to 2007.
He was disqualified from the shorter race at the Deagu world championships in 2011, however, and flirted with a similar mishap when he stumbled out of the blocks in the semi-finals earlier on Sunday.
There were no mistakes when it came to final, though, and, he powered down lane five to edge Gatlin at the line.
The 33-year-old American will perhaps regret dipping for the line quite so far out, a move which disrupted his rhythm and reduced his speed.
“I feel good, on the last five metres I kind of stumbled and it cost me my momentum,” said Gatlin, a world and Olympic champion before his second doping ban and the rise of Bolt.
“Everybody wants to come out and win but I got nabbed by the great Usain. I’ll have a day off and come back and be prepared for the first round of the 200.”
Bolt will go for successive world championship sprint sweeps in Beijing with the 200 metres final scheduled for Thursday.
(Reporting by Nick Mulvenney, editing by Pritha Sarkar)