In 1929, after receiving his degree from Kyoto Imperial University, he stayed on as a lecturer for four years. After graduation, he was interested in theoretical physics, particularly in the theory of elementary particles. In 1932, he married Sumi Yukawa (スミ). In accordance with Japanese customs of the time, since he came from a family with many sons but his father-in-law Genyo had none, he was adopted by Genyo and changed his family name from Ogawa to Yukawa. The couple had two sons, Harumi and Takaaki. In 1933 he became an assistant professor at Osaka University, at 26 years old.