ONE Championship 2014–2016: Early career & ONE Strawweight World Champion Amnuaysirichoke began his professional MMA career in 2014 for
ONE Fighting Championship. On June 14, 2014, Dejdamrong made his debut at
ONE FC: Era of Champions, where he defeated Jomanz Omanz by first-round TKO. He started out undefeated at 6–0, including a win over Roy Doliguez on May 22, 2015, to claim the ONE Strawweight World Championship, becoming the most successful Thai mixed martial artist and first Thai world champion in MMA. Dejdamrong was the ONE World Champion for over a year before losing the title to
Yoshitaka Naito on May 27, 2016. Since losing the Strawweight World Title, Dejdamrong has gone 5–4 in ONE Championship.
2017 On March 11, 2017, he lost to future ONE Strawweight World Champion
Joshua Pacio by split decision at
ONE Championship: Warrior Kingdom. On May 26, 2017, Dejdamrong defeated Adrian Mattheis by first-round KO at
ONE Championship: Dynasty of Heroes. On August 18, 2017, he stopped Robin Catalan by TKO in the second round at
ONE Championship: Quest for Greatness. On December 9, 2017, Dejdamrong lost to Riku Shibuya by second-round submission via
guillotine choke at
ONE Championship: Warriors of the World.
2018 Dejdamrong then lost to Jeremy Miado by first-round KO on March 24, 2018, at
ONE Championship: Iron Will. 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.
2019 Dejdamrong faced Jeremy Miado in a rematch on February 22, 2019, at
ONE Championship: Call to Greatness. This time, he was able to secure a second-round TKO victory. He then faced Miao Li Tao on May 17, 2019, at
ONE Championship: Enter the Dragon, where he lost by first-round knockout. 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.
2020 Dejdamrong competed only once in 2020. On October 10, 2020, he faced Hexi Getu at
ONE Championship: Reign of Dynasties. After getting dominated on the ground over three rounds, he lost by split decision.
2021 Dejdamrong is scheduled to face Banma Duoji at
ONE Championship: Battleground 3 on August 27, 2021. He won by technical knockout in the second round.
2022 Dejdamrong faced Danial Williams at
ONE: Bad Blood on February 11, 2022. He lost after a liver punch stopped the bout in the second round.
Retirement Following his fight with Williams, Dejdamrong announced his retirement on
Instagram. ==Championships and accomplishments==