While attending Keio University, he was inspired by the works of Kyōka Izumi and by a newly appointed professor, Kafū Nagai, who was also the founder of the literary magazine Mita Bungaku, launched in 1910.

While at Keiō University, Minakami developed a friendship with the playwright, script writer, and director of the Bungakuza Theater, Mantarō Kubota.

After a period overseas, studying economics in the United States, and touring 16 countries around the world, Minakami returned to Japan in 1916 to accept a position in his father's insurance company.

However, he did not give up his literary aspirations, and this job provided him with an insight into the lives of white-collar workers, albeit from the rather lofty position of director of one of Japan's largest insurance companies.

Minakami wrote numerous novels in the 1920s and 1930s depicting the lives of common, urban people.