The Jamaican sprint king won in 9.87sec, the same time he set in winning his heat earlier in the evening, on a cool, damp night at the London Olympic Stadium.
Friday's was his first appearance in six weeks with his only previous 100m race this year seeing him struggle to a modest 10.12sec in Brazil.
Justin Gatlin of the United States still leads the way with 9.74sec in the 100m this season, setting up an intriguing world championship showdown with Bolt in Beijing next month.
"I feel like I am getting there and that's the good thing."
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Michael Rodgers was second in the final in 9.90sec with Kemar Bailey-Cole of Jamaica taking second in 9.92sec.
"I need to work hard ahead of Beijing. I have to keep pushing myself," added 28-year-old Bolt who was running on the track where he won the 100m, 200m and 4x100m relay gold at the 2012 Olympics.
Bolt announced his return to form in the heats an hour and 20 minutes before the final on Friday.
After Britain's world indoor 60m champion Richard Kilty had been disqualified for a false start, Bolt made a hesitant start when the race got underway at the second time of asking.
But he overhauled Rodgers as he eased across the line in 9.87sec, the American finishing runner-up in 9.92sec.
It was the Jamaican's fastest time since September 6, 2013, when he clocked 9.80sec at the Brussels Diamond League meeting.