Takeuchi graduated from Kokugakuin College.
While working in Nagano Prefecture as primary school teacher in his early twenties, Takeuchi published a local history of Kawashima Village in Kami Ina District. This created a wave of interest in the study of local education.
In 1952 Toshimi became professor of Tohoku University. Later he was appointed a professor of Liberal Arts Faculty there and director of Japan Local Culture Research Institute.