The US, who have also won four of the last five Olympic golds, came home well clear in 2:57.31.
Quincy Hall (25) and Vernon Norwood (31) built an early lead before Justin Robinson (25), who also got a gold in the mixed 4x400 on the opening night, stretched it to give anchor Rai Benjamin (26) ca virtual lap of honour.
France took silver as a national record 2:58.45 gave them their first medal of the championships in the penultimate event.
Britain took bronze in 2:58.71, holding off back to back silver medallists Jamaica.
Dutch delight
Femke Bol (23) produced an astonishing final leg to snatch gold for the Netherlands in a thrilling women’s 4x400 metres relay on Sunday, the final event of the World Championships.
Anchor Bol took the baton in third place, almost 20 metres adrift of leaders Jamaica and behind Britain and was still well adrift of both going into the final straight.
Bol, who fell just short of the finishing line in the 4x400m mixed relay on opening night then won individual gold in the 400m hurdles, overhauled Britain's Nicole Yeargin (26) and then edged Jamaica's Stacey Ann Williams (24) on the line.
The Dutch clocked 3:20.72, Jamaica’s second successive silver came in 3:20.88, with Britain taking bronze in 3.21.04
The United States women, who had won seven of the last eight World Championships and the last seven Olympic golds, were absent after being disqualified after a botched baton changeover in the semi-finals.