Just last year Peaty was considering quitting the sport for good, describing his troubles as a “self-destructive spiral”.
Those issues came to a head after he broke his foot in 2022, which led to the end of his incredible eight-year unbeaten run over 100m.
After returning last autumn, he won bronze at this year’s World Championships and qualified fastest for this final ahead of China’s Qin Haiyang.
Qin, the 2023 world champion who was expected to be Peaty’s main rival for gold, led the Briton by 0.05 seconds at the turn before fading.
Peaty moved into the lead halfway down the final length before Martinenghi, the bronze medallist from Tokyo, came through in the final strokes with Peaty and Fink touching the wall at exactly the same time.
Peaty became emotional afterwards as he spoke about his difficult recent years and there were more tears after the medal ceremony when he hugged his three-year-old son.
“It has been a very long way back,” said Peaty. “I gave it my absolute all.
“It is just incredibly hard to win it once, and again, and again, and trying to find new ways to do it.
“I can’t have that relentless pursuit every single day without a sacrifice of some sort and that sacrifice can come in different ways – time, energy, relationships.”
He refused to be drawn on his future after the race, instead insisting his focus remains on the relays later in the meet.
