[3] Sophorn's began in Kun Khmer boxing by training at the Taley Domrei Mean Rith Club,[4] where he was inspired by his brother, Phal Sophat, a Cambodian national boxer.

[5] In 2016, Phal Sophorn defeated Vong Noy to win the 63.5 kg Cambodia Beer Championship at Bayon Boeung Snor.

[10] Despite Long Ben Loeun's vow to defeat Phal Sophorn and win his first-ever title, he collapsed during their final match in ring of Town Arena.

Sophorn became the first Cambodian fighter to win the International Professional Combat Council's Kun Khmer 63.5kg World Championship, organized by Town Arena.

[14] On September 30, 2023, Phal Sophorn won a Wurkz World IPCC Kun Khmer title after defeating Changpuak Jetsada by points.