He was born on 20 April 1911 at Sing Buri Province into an cadet branch of Chakri Dynasty with Chinese ancestry. The son of Brigadier General Prince Khamrob and his wife Daeng (Bunnag), his older brother was M.R. Seni Pramoj while his great-grandmother, Ampha, was of Chinese descent and was a consort of Rama II. He served as a corporal during the Franco-Thai War in 1940. Like many upper class Thais of his generation, his parents sent him and his siblings to boarding schools in England including Trent College. He finished his bachelor's degree in Philosophy, Politics, and Economics (PPE) from Queen's College, University of Oxford.