His early interests in the Thai folk theatre form Likay were curtailed by his father, who encouraged him to pursue boxing instead.
During his incarceration, he taught boxing to fellow inmates and continued to compete, winning the WBC Asia Continental Welterweight title.
In October 2014, Sirimongkol defeated Dan Nazareno Jr. to win the WBO Asia Pacific junior middleweight title.
His 51-fight winning streak was finally broken in 2017 by Uzbek boxer Azizbek Abdugofurov in an unsuccessful bid for the WBC Asia middleweight title, marking his first defeat in 14 years.
[6] Sirimongkol, known for his striking appearance, was dubbed "Teppabud na yok" ("handsome divinity") by his Thai boxing fans.
His ventures included modeling for a women's fashion magazine, appearing on the 2003 Thai TV drama "Pret Wat Suthat" on Channel 7 and the 2008 martial arts film "Chocolate", and featuring in a music video by the rock band Motive alongside Dom Hetrakul.