Inukai attended the School of Philosophy in Tokyo Imperial University, but he left without graduating and became a writer.

Interested in literature from his student days, he gravitated to the Shirakaba ("White Birch") literary society due to its liberal and humanistic outlook.

After his father's assassination in the May 15 Incident, he continued to strive for restoration of good Sino-Japanese relations, and especially provided support to the Wang Jingwei government in hopes that it would bring the stability that would allow Japan to withdraw its troops from the China quagmire.

Thus throughout 1938 until the formation of the Reorganized National Government of the Republic of China in 1940, he negotiated with Gao Zongwu and Mei Siping to come to a peace agreement with Chiang Kai-shek, and after failing that, to organize the defection of Wang Jingwei.

In the 1942 General Election, Inukai was reelected as an independent candidate opposing the Imperial Rule Assistance Association.

After the surrender of Japan in 1945, Inukai was appointed parliamentary vice minister for foreign affairs under the Shidehara cabinet.

However, as many Diet members had been affiliated to the Imperial Rule Assistance Association the party was severely hurt by purges.

Ashida took over as prime minister and tried to hold the coalition together, but had to resign in October 1948 due to bribery scandals.

[1] His son Yasuhiko was president of Kyodo News, and his daughter Michiko (d. 2017) was an author and a philanthropist.