The Jamaican collected his fourth career Olympic gold ahead of world champion team-mate Yohan Blake, who clocked 9.75 for silver, with 2004 champion Justin Gatlin taking the bronze in 9.79 seconds.
“I knew it was going to be like this,” Bolt said with typical self-assuredness.
Bolt’s world record of 9.58 seconds, posted in 2009, remained intact, but it was still the second fastest 100 metres time of all time.
The 25-year-old got off to a customary slow start, but switched gear at 50 metres to storm past Gatlin and Blake and across the line.
Bolt adds the title to the 100 metres, the 200 metres, and the 4 x 100 metres relay gold medals he won in Beijing.
The 2007 world champion Tyson Gay came fourth with 9.80.
Earlier in the evening, Team GB runner Christine Ohurugu took silver in the final of the women’s 400m.
Her main rival, the US’s Sanya Richards-Ross, took gold, but Ohurougu came from nowhere to put in a powerful late charge to take second place.