After briefly commanding the 3rd battalion of his regiment, Masters subsequently became GSO1 (the Chief of Staff) of Indian 19th Infantry Division, which was heavily involved in the later stages of the Burma Campaign, until the end of the war. On 17 January 1946 he was awarded an OBE for his service in Burma. After a spell as a staff officer in GHQ India in Delhi, he then served as an instructor at the British Army Staff College, Camberley. He left the army after this posting, and moved to the United States, where he attempted to set up a business promoting walking tours in the Himalayas, one of his hobbies. The business was not a success and, to make ends meet, he decided to write of his experiences in the army. When his novels proved popular, he became a full-time writer.