Rutherford delighted the crowd inside the Olympic Stadium with an 8.31m jump to take top spot.
His win kept the feelgood mood going, coming just minutes after the stadium erupted with noise following Jessica Ennis's Heptathlon gold.
Other than Ennis, Rutherford was the only British athlete to lead the world rankings in his event this year but had largely slipped under the radar.
Host Nation Britain had not won gold in the men's Long Jump since Lynn Davies's win in 1964.
But Rutherford produced his best to take the title, ahead of Mitchell Watt of Australia and Will Claye of the USA.