The 22-year-old Olympic champion, who had lowered the world championship trophy in qualifying, clocked 57.47 seconds – 0.34 outside his own world record.
Peaty told BBC Sport: “You aim for world records, but they are world records for a reason.”
Kevin Cordes (58.79) took silver with Kirill Prigoda (59.05) third.
Peaty’s fellow Briton Ross Murdoch was eighth.
“I felt like a little boy again going out to the crowd,” said Peaty, who has now set the top 10 times in the world.