Takemi completed his M.D. in 1930 from Keio University School of Medicine. He went to RIKEN to study the application of nuclear physics to medicine under Yoshio Nishina who was a famous physicist in Japan.
He became a clinician in Ginza, Tokyo in 1939, and served as a visiting professor at Keio, Kitasato, and Tokai universities in Japan, and advised the Japan Science and Technology Agency. In 1982, he was appointed a visiting professor at the Harvard School of Public Health, but was unable to fulfill the commitment due to illness. He died in Tokyo in December 1983.