In 2012, Sangmanee was named Muay Thai Fighter of the Year by the Sports Writers of Thailand at the age of 15.
On October 11, 2012, Sangmanee added another Muay Thai title to his résumé by defeating Kudsakornnoi Sor Junlasen for the S1 110lbs World Championship.
[4] Following his rise to prominence in Thai stadium scene, Sangmanee found more success competing in the Top King World Series tournaments.
He made his Top King World Series debut at TK3 in Hong Kong on December 20, 2014, where he defeated Man Kwok by unanimous decision.
On January 14, 2017, at TK12, he fought to a draw with future ONE Muay Thai bantamweight title contender Han Zihao.
On September 16, 2019, Sangmanee signed a multi-fight contract with the Singapore-based organization ONE Championship to compete in the all-striking ONE Super Series format.
[7] Sangmanee faced Kulabdam Sor.Jor.Piek-U-Thai in the semi-finals of the ONE Bantamweight Muay Thai Tournament at ONE Championship: No Surrender 3.