The popular event was first run in 2019 when the U.S. won and they dramatically triumphed again in 2023 after managing only bronze on home soil in Eugene in 2022.
Victory was never in doubt on Saturday, however, as they came home well clear in an equal championship record of three minutes 08.80.
Bryce Deadmon, who has Olympic silver and bronze in the event in his cabinet, gave them an early lead and Lynna Irby-Jackson consolidated it before Jenoah McKiver scorched a 43.91 third lap to leave the pack trailing in the distance. Alexis Holmes had the honour of crossing the line.
Femke Bol, who famously fell metres from the line to hand the U.S. the gold in the last worlds, delivered another outstanding anchor leg to give the Dutch the silver in 3:09.96.
Fast-finishing Belgium took bronze in 3:10.61 - their first global medal in the event.
"With the three guys behind me, I knew I was going to be alright," said Deadmon, who also has two 4x400m men's relay golds to his name.
"I told my teammates to trust themselves. They have been running 400s all year and if they did the same, things would work out as they are supposed to."
