Narantungalag had a slow start to his mixed martial arts career, losing his first two professional bouts to UFC veteran Norifumi Yamamoto in 2004, and Toshikazu Iseno in 2006, via KO and unanimous decision respectively. Following this though, he would go on a four fight winning streak, and also won the Mongolian MMA Championship Tournament in 2010, defeating both Burenzorig Batmunkh and Otgonbaatar Nergui via submission. After the impressive victories, Narantungalag signed with upstart promotion Sengoku Raiden Championship.
World Victory Road
After signing with the promotion, Narantungalag faced Pride FC and UFC veteran Akihiro Gono at WVR: Sengoku Raiden Championships 14 on August 22, 2010. He won the fight by unanimous decision. In his second fight with the promotion, Narantungalag faced Kazunori Yokota at WVR: Soul of Fight in the promotion's final event on December 30, 2010. He won the fight via first-round knockout, bringing his winning streak to six in a row.
Legend Fighting Championship
Narantungalag faced Adrian Pang at Legend FC 6 on October 30, 2011, for the LFC Lightweight Championship. He won the fight via split decision. In his first title defense within the promotion, Narantungalag faced Korean prospect Yui Chul Nam at Legend FC 8 on March 30, 2012. He successfully retained the championship, winning the fight via second round guillotine choke. For his next fight in the promotion, Narantungalag faced Koji Ando at Legend FC 11 on April 27, 2013. He would lose the championship bout in the third round, after suffering a broken ankle.
ONE Championship
In April 2014, Narantungalag signed with Singapore based promotion ONE Championship. He made his debut against the former ONE Featherweight Champion, Honorio Banario at on May 30, 2014. After three rounds, Narantungalag would win the fight via unanimous decision, handing Banario his third straight loss. Narantungalag faced Koji Oishi for the ONE Featherweight Championship at ONE FC 19: Reign of Champions on August 29, 2014. He won the fight by unanimous decision to become the new ONE Featherweight champion. Narantungalag was set to defend his title for the first time against Eric Kelly at. ONE FC & Kelly's management team could not see eye-to-eye and the negotiations fell through. Narantungalag was then set to defend his title against the undefeated Russian Marat Gafurov at but visa trouble but a halt to that and Gafurov then fought Martin Nguyen for the ONE interim Featherweight Championship. Narantungalag and Gafurov finally met at to unify the ONE Featherweight Championship. He lost via rear-naked choke in the fourth round. In his first fight of 2016, Narantungalag was set to face former ONE Lightweight ChampionKotetsu Boku at. He won via Von Flue choke in the third round. He returned in July of the same year to KO Eric Kelly, before losing to Gafurov in their rematch in November. Following a forced hiatus due to injury, Jadambaa returned in 2018 and picked up back-to-back victories over Edward Kelly and Kazuki Tokudome. These victories earned him another shot at the world title against Martin Nguyen at.
