Ambassador Sugiyama presented his credentials as Ambassador to the United States in March 2018. His diplomatic career with the Japanese Ministry of Foreign Affairs (MOFA) spans over 40 years. He most recently served as Vice Minister for Foreign Affairs. Previous positions include Deputy Director-General of the Middle Eastern and African Affairs Bureau as well as the International Cooperation Bureau; Director-General for Global Issues, including Ambassador for Climate Change; and Director-General of the Asian and Oceanian Affairs Bureau.
Ambassador Sugiyama has also held leadership positions within the Foreign Policy Bureau and Treaties Bureau of MOFA. His overseas assignments have included multiple positions at the Embassy of Japan in Washington, DC; Political Minister at the Embassy of Japan in Korea and Deputy Chief of Mission at the Embassy of Japan in Egypt. He entered MOFA in 1977.
Ambassador Sugiyama studied at Waseda University in Japan and Oxford University in the UK. He has taught international law for many years at the law faculty of Waseda University, as well as at many other schools in Japan and overseas, and has written numerous law articles, edited books on international law, and served as a member of the editing committee of the international law journal issued by the International Law Association of Japan.
He is married to Yoko E. Sugiyama and they have two children: a son, Shunsuke D., who runs his own company in Hyogo Prefecture in Japan and has four children; and a daughter, Reina C., who graduated from Parsons in New York and has worked as a fashion designer there for nearly 16 years. Ambassador Sugiyama was Christened at University College, Oxford. He and his family are Episcopalians.