The 21-year-old came from fifth place in last 50 metres to claim glory
The 21-year-old Floridian came from fifth place and trailed German Florian Wellbrock at the final turn and needed every ounce of strength and speed to touch first at the end of the long-distance race.
Finke edged out Italian Gregorio Paltrinieri into silver medal position, and Mykhailo Romanchuk of Ukraine landed the bronze medal, ahead of Wellbrock in fourth place.
Finke’s thrilling win came just days after he broke the American record for the distance during his qualifying heat in Tokyo.
The Clearwater native graduated from Countryside High and is now a senior on the University of Florida’s swim team.
The 6ft tall athlete was nicknamed “wildman” as a child, his parents told News Channel 8.
“Because he’s not afraid to do anything,” said his dad, Joe Finke.
“The lifeguards would say Bobby is coming, we have to put another lifeguard in the chair! haha,” added his mother, Jeanne Finke.
Finke’s sister, Summer Finke, took to Twitter to celebrate his victory.
“MY BROTHER IS AN OLYMPIC GOLD MEDALIST," hun skrev.