Nidhi Eoseewong was born on 23 May 1940,[2] to an ethnic Chinese family in Chiang Mai, Thailand.

He studied at Assumption College Sriracha in Chonburi Province, and went on to earn bachelor's and master's degrees in history from Chulalongkorn University in Bangkok.

Upon graduation, he accepted a position teaching history at Chiang Mai University, where he would go on to spend the majority of his professional career.

He took temporary leave to continue his studies, completing a PhD from the University of Michigan in 1976.

He was an important contributor to the website Midnight University, regularly publishing and making appearances.