Graduated from Political Science Department of Tokyo University (1926).
Katsuzo Okumura entered Foreign Ministry and served as 2nd Secretary at Japanese Embassy in Sydney, chief of 2nd Section of East Asia Bureau of Foreign Ministry and director of Information Department. Became director and chief of General Affairs Department of Kashima-Gumi Civil Engineering & Construction Company (1948). Rejoined Foreign Ministry and became vice-minister of Foreign Affairs (1952). Served also as member of Scientific Technique Administrative Council. Nominated Japanese Ambassador to Switzerland (February, 1957).