He's the first Brit to win a gold swimming medal since David Wilkie in 1975.
Gibson even beat world record holder Oleg Lisogor from the Ukraine, who came second.
"I feel fantastic," Gibson said. "I had a good start - they had to come out to beat me today but I made sure that in my head they wouldn't do it."
Another Brit, Ian Edmond, also did well by smashing his own record in the 200 metres breaststroke.