I Gusti Gde Subamia was born on 4 May 1921, in the town of Tabanan, in the island of Bali. Little is known of his early life, but he began his career as an assistant district head in 1940. During the Japanese occupation, he left the position of district head, and became police officer and customs officer in Giliamanuk, and later his hometown of Tabanan. In 1946, following the proclamation of independence and the beginning of the national revolution, he became a clerk and moved to Denpasar.
