Kunihiko Kodaira was born on March 16, 1915, in Tokyo. Kunihiko Kodaira's parents were Gon-ichi (1884-1976) and Ichi Kodaira (1894-1993). Gon-ichi, Kunihiko's father, had studied agriculture and politics at Tokyo Imperial University and, at the time his son was born, was working at the Ministry of Agriculture. He retired from the Ministry of Agriculture in 1939 and was elected to the Japanese Parliament where he served during World War II. After Japan was defeated, the Allies removed him from public office. In addition to these activities, he wrote around 40 academic books and 350 academic papers. Ichi, Kunihiko's mother, was the daughter of the schoolmaster Kyuji Kanai. Kunihiko was the eldest of his parents' sons, having a younger brother Nobuhiko (born in 1919).