Pairojnoi is an orphan who grew up in the Chachoengsao province, in a temple known for taking care of homeless children.
He started Muay Thai training at the age of 9, he had his first fights in the nearby temples.
[1] In 1985 he was scouted by the Songchai promotion and began his ascension at Lumpinee stadium in the 105 lbs division where he became popular for his aggressive style.
[2] Pairojnoi's fight against Pongsiri Por Ruamrudee on July 25, 1989, was the headline bout for a card that broke records at Lumpinee stadium with a 3 million baht gate and over 10,000 spectators.
He was working at the Kor Romsritong camp until its closure, he then joined the Sitsongpeenong before opening his own gym in Samut Sakhon.