Peaty, a dominant force in breaststroke events for almost a decade, became the first British swimmer to retain an Olympic title when he took gold in the 100m at the Tokyo Games in 2021.
He missed the 2022 World Championships because of a foot injury, and was unavailable last year after stepping away from the sport to prioritise his mental health.
The world record holder told the BBC last week he had arrived in Doha “at peace” after his difficulties.
While some top swimmers are skipping the championships to focus on Paris 2024, Peaty is using the event as part of his preparations for his bid for a third successive Olympic 100m gold in the French capital this summer.
Having qualified third fastest in the heats to reach the semi-finals, Peaty improved his time to finish as the fastest qualifier for the final, ahead of American Nic Fink (58.73) and the Netherlands’ Arno Kamminga (58.87).
“I feel good,” Peaty said after qualifying for the final. “My objective for this meet was to progress through the rounds, progress physically and in results, but also progress mentally and see what strategies are working, what isn’t working.
“It’s more of a test event for us, but obviously we’re going to put our best foot forward and put a good fight on.
“After the heats I was like, ‘okay, I know what I’m working with and I know what I’m capable of’. But tonight was just about going out there, showing a little bit of Adam Peaty which is a front end, getting a little bit angry with myself like I normally do. Tonight I showed that I can still get it down that back end when I really need to.”
Fellow Briton James Wilby went out in the heats.
