Manasak was born in the Rayong Province where he started Muay Thai during the mid 1970s.
Manasak then joined the Sor Ploenchit camp in Bangkok under the teaching of Sathien Sathiensut and became a successful fighter.
[2] During his prime in the 1980s Manasak was known as a highly skilled fighter with a complete arsenal and some of the sharpest eyes in the ring.
He beat many notable fighters of his era such as Kongtoranee Payakaroon, Saencherng Pinsinchai, Sangtiennoi Sor.Rungroj, Panomtuanlek Hapalang, Jaroenthong Kiatbanchong or Chanchai Sor Tamarangsri.
[3] As of 1987 Manasak was a two time Rajadamnern Stadium champion and won the Thailand King's belt.