金門砲戦
After the war, Green was discharged from the Navy and joined the Foreign Service. His first posting was as Third Secretary at the Embassy of the United States in Wellington. Over the next decade, Green rose rapidly through the ranks of the Foreign Service, ultimately becoming principal assistant to Secretary of State John Foster Dulles; he was Dulles' principal assistant at the time of the Second Taiwan Strait Crisis, which brought the United States and China to the brink of war.