The Jamaican sprinter finished in 9.78 seconds to edge out America's Justin Gatlin, but admitted that he was targeting a faster time.
"I am happy but I wanted to do better," he told BBC Sport. "My legs were sore after the semi-finals, I don't know why, but the world record wasn't on so I came out just to win.
"Back in Jamaica, they do not expect less than that from me. They always expect me to dominate."
The result saw Bolt claim his fourth individual World Championships gold.