Bolt, 25, the Jamaican world recordholder and defending Olympic champion, exploded down the track at London's Olympic Stadium and won the gold medal Sunday night in a blazing time of 9.63.
It broke his Olympic record set in Beijing — 9.69 — and was just .05 off the world record of 9.58 he set in 2009.
During introductions, Bolt made a series of hand gestures, then smiled.
Much had been made about the possibility of bad weather preventing fast times on the Olympic Stadium track.
But on Sunday night, just before 10 p.m. London time, when the fastest men in the world lined up to see who is fastest, the weather was perfect.
Yohan Blake, Bolt's training partner and world champion from last year, was second in 9.75 seconds.
Team USA's Justin Gatlin, the 2004 Olympic champion who served a four-year doping suspension ending in 2010, earned the bronze with a time of 9.79.
Tyson Gay of the USA was fourth (9.80) and Ryan Bailey of the USA was fifth (9.88).
Gay, 29, who was battling injuries in 2008 and didn't make the final, was in tears in the mixed zone after the race.
"I don't think I could go back and do nothing else," Gay said, choking up. "I feel like I ran with the field. I just came up short. That's all I did."
Gay is the second-fastest man in history at 9.69 seconds.
And once again Jamaica gets the better of the USA in the sprint rivalry. On Saturday night, in the women's 100, Jamaica won gold and bronze and the USA got silver.
The anticipation could hardly have been greater, for a lot of reasons.
The main question was whether we would see the Beijing Bolt again or the lesser version that had been on display this season.
In Beijing, Bolt ran three races and set three world records — 9.69 in the 100, 19.30 in the 200, plus a third world record on the Jamaican winning 4x100 relay.
The next year, at the 2009 world championships in Berlin, he lowered those marks to 9.58 in the 100 and 19.19 in the 200.
And there those records have remained.
In 2010, Bolt's fastest time was 9.82. Last year, his fastest was 9.76, and he was disqualified for a false start in the 100 meters at the world championships in Daegu, South Korea.
This season, again 9.76 is his fastest time, and he was beaten twice by 22-year-old Jamaican training partner Yohan Blake — in the 100 and 200, both times at the Jamaican Olympic trials.
People have wondered if he was 100% healthy. He was bothered earlier this year by a back issue which morphed into a tender hamstring.
Also, people have wondered if Bolt was worried in the blocks about false starting, unable to shake the mishap in Daegu.
He has said that's not the case, and he has shrugged off criticism of his start with a rather unusual explanation.
"We have come to the conclusion that back in the day, I was never a good starter, and I'm never going to be a great starter," Bolt said a few days before the Games, referring to himself and his coach, Glen Mills. "So I should just get past that and focus on just running. I'm not worried about the start. It's all about execution and getting it right at the end of the race."
But there was still this to wonder: what exactly is getting it right for Bolt now, at age 25, four years after electrifying the Beijing Olympics with his prancing and preening but most of all his explosive speed?
Is another 9.76 getting it right?
Does he have another 9.6 again? Or even a 9.5?
In round 1 in London Saturday, he stumbled out of the blocks — another sluggish start for the 6-5 Bolt — and lumbered to the line in 10.09 seconds.
During introductions for his semifinal heat Sunday evening, he struck a boxing pose and threw a right and a left.
Then he looked as comfortable as could be, starting pretty well, driving through the halfway point like an Olympic champion would, and then easing up at the finish with a big lead. His time — 9.87 — impressive for how easy he took the finish.
Even if Bolt's days of running 9.5 and 9.6 are over, the excitement about this race was palpable. Few experiences in sports rival the drama of eight men crouching into the blocks of an Olympic 100 meters final.
It's over in less than 10 seconds.
And when it is, heroes are celebrated, reputations have been altered and maybe even Olympic careers ended.
Gatlin, who served a four-year doping suspension after his 2004 Olympic gold in the 100, will be 34 in 2016. Gay will be 33, and he has said this will likely be his last Olympics.
In Bolt's case, his career almost certainly goes on for years. He is just 25, after all. For him, the career-arc question is about his stated goal: to be a legend.
If the Beijing Bolt was to return, that goal figured to be assured. But in the days and hours leading up to the race, it was a significant "if."
It's not anymore. The Beijing Bolt is back.