Kunoi was born on November 6, 1933, in Bangkok's Yaowarat neighborhood to overseas Chinese immigrants living in Thailand.
He started with Muay Thai by fighting regularly at Rajadamnern Stadium and later switched to professional boxing.
In the last fight, he was defeated by points decision over the 10 rounds, losing the Rajadamnern Stadium flyweight championship.
[2] After Pone Kingpetch became world flyweight champion, he stated in an interview that Kunoi Vithichai was his best opponent, as opposed to Pascual Pérez or Fighting Harada.
In the boxing community, he was a trainer for three Thai boxers who later became world champions: Saensak Muangsurin, Napa Kiatwanchai and Muangchai Kittikasem.