[5] Early in his career after his stint in wrestling, Romanov found Chelsea Edward, a Muay Thai coach.

[5] Romanov compiled a record of 11 wins and no losses while competing in his native Moldova, primarily at Eagles Fighting Championship, where he became the heavyweight champion.

[6] Romanov signed with the UFC on October 3, 2019, and was later scheduled to make his debut against Raphael Pessoa on April 25, 2020.

[10] Romanov eventually made his debut on September 12, 2020, at UFC Fight Night: Waterson vs. Hill, when he defeated Roque Martinez via arm-triangle choke in the second round.

[11] Next, he faced Marcos Rogério de Lima on November 7, 2020, at UFC on ESPN: Santos vs. Teixeira.

He defeated Lima with the first forearm choke in UFC history, on the first round, to claim Performance of the Night honors.

[19] Replacing Rodrigo Nascimento, Romanov is scheduled to face Tanner Boser on April 23, 2022, at UFC Fight Night 205.

[22] However, Sherman was deemed unable to compete due to a minor health issue on the day of the event and the fight was cancelled[23] and the pair was rescheduled for UFC on ESPN 35.

[36] Despite having a recent win, on November 5, 2024, it was reported that Romanov's contract was not renewed, so he was removed from the UFC roster as a result.

[37] On January 27, 2025, Romanov reported at Instagram account that he signed with Professional Fighters League.

[42] Romanov competed against Dymere Rappa in the main event of Fury Pro Grappling 12 on December 28, 2024.