Novelist. He entered Waseda University and worked actively as a public speaker, engaging in the Freedom and People's Rights Movement and socialist activities, but eventually switched to being a novelist. In 1921 his novel Gokuchcu Yori (From the Jail) won the competition held by Jiji Shinpo, and he published Tohiko (Escape) the same year, with which he debuted in the literary world. In 1935 Jinsei Gekijo (The Theater of One’s Life) (1933-36) was highly praised by Kawabata Yasunari, and Ozaki became a popular writer. During the war, he accompanied the Japanese army to the battlefield and also wrote Ishida Mitsunari (1938) and Takasugi Shinsaku (1941) in serialized form. In the post-war period he turned to writing historical novels. After his passing he received the Person of Cultural Merit award.