In 2013, when Theara was 15, after a visit to his hometown in Prey Veng with his parents, the family moved back to Cambodia and worked "for a brick making business nearby Phnom Penh.

[6] On July 16, 2023, for his return to the ring after breaking his right arm in April 2023, Theara defeated Romanian Alex Bublea, at the 72 kg weight class to win the Techo Santepheap Kun Khmer World Championship belt.

[7] On January 1, 2023, after he defeated two top ranked Muaythai fighters in Saiyok Pumpanmuang and Beckham Banchamek, the World Muaythai Organization (WMO) recognized Kun Khmer and put Theara in first place in the world ranking 72.5 kg weight category, becoming the first Kun Khmer athlete to be recognized by the World Muaythai Organization (WMO).

Joe Ryan fought Petchmai and claimed the vacant Rajadamnern Stadium middleweight title.

[12] [13] In a South Korean Kun Khmer event, Thoeun Theara is scheduled to fight Victor Teixeira, a Brazilian world champion who notably defeated Kongthailand Kiatnavy at ONE Friday Fight 20.