Prior to mixed martial arts, Dejdamrong was a Muay Thai fighter with 350 fights who won multiple Lumpinee Stadium titles in three different weight classes.
On June 14, 2014, Dejdamrong made his debut at ONE FC: Era of Champions, where he defeated Jomanz Omanz by first-round TKO.
On March 11, 2017, he lost to future ONE Strawweight World Champion Joshua Pacio by split decision at ONE Championship: Warrior Kingdom.
[10] On December 9, 2017, Dejdamrong lost to Riku Shibuya by second-round submission via guillotine choke at ONE Championship: Warriors of the World.
[12] He would bounce back with a second-round submission victory over Himanshu Kaushik via rear-naked choke on November 9, 2018, at ONE Championship: Heart of the Lion.
[15] Nevertheless, Dejdamrong was able to close out 2019 on a high note with a third-round TKO victory over Muhammad Imran on November 22, 2019, at ONE Championship: Edge Of Greatness.