Taylor's season's best mark of 17.81 metres was enough to finish ahead of U.S. compatriot Will Claye, who took silver with a jump of 17.62 metres. Italy's European champion Fabrizio Donato, 35, finished in bronze with a jump of 17.48 metres.
Taylor, already the leading jumper in the world this year with a mark of 17.63 set in June, missed his first two jumps and only landed three all night. His fourth attempt was the one that mattered, though, taking him above Claye who had been leading.
The 22-year-old had finished second behind 21-year-old Claye at this year's world indoor championships and after injuries to other contenders the Olympic gold medal was only ever likely to go to one of the two Americans.
Britain's injury-hit former world triple jump champion Phillips Idowu failed to make the final and Frenchman Teddy Tamgho, the third man on the all-time list, pulled out of the Games in June with a foot problem.
Leevan Sands of the Bahamas, bronze medallist four years ago in Beijing, was forced to retire after injuring his knee on his fourth attempt.
The 30-year-old began the final with a strapped knee but it gave way during a jump and he was stretchered out of the sand.
The silver for Claye was his second medal of the Games after winning bronze in the men's long jump final.