Phetphuthai's parents are ethnic Phu Thai from Nakhon Phanom, though Phetphutai himself was born and raised in the Bang Na District of Bangkok.
He started boxing in kindergarten, inspired by his father who was a former boxer, and who would be Phetphuthai's first trainer.
As life was very tough for his family, he would help his parents sell grilled squid everyday after practice.
At 13 years old, while still under his father's guidance, he won his first fight at the famed Rajadamnern Stadium by decision (84 lbs).
In 2016, when he was 14 years old, Petphuthai was contacted by Sia Phairot Punpho of Sitsarawatseua gym,[2] and he has been training there under Kru Gai ever since.