長崎大学
After returning to his homeland, Yoshida served as a professor of pathology at Nagasaki University from 1938 to 1944, Tohoku University from 1944 to 1952, before being appointed as a professor of pathology at the Faculty of Medicine, University of Tokyo in 1952, where he became a dean in 1958. In addition, he became a director at the Sasaki Institute in 1953 and at the Cancer Institute, Japanese Foundation for Cancer Research in 1963.