Inukai's first cabinet post was as Minister of Education in the first Ōkuma Shigenobu administration of 1898, succeeding Ozaki Yukio, who was forced to resign due to a speech that conservative elements in the Diet charged promoted republicanism.

He was also a strong supporter of the Chinese republican movement, visiting China in 1907, and subsequently lending aid to Sun Yat-sen during the Xinhai Revolution of 1911 which overthrew the Qing dynasty.

[4] Although in later years his vision of Sino-Japanese cooperation diverged greatly from Sun's, Inukai maintained close personal ties with many leading Chinese politicians.

He was concurrently Education Minister again for a four-day period in September 1923 In 1922 the Rikken Kokumintō became the Kakushin Club, and joined forces with other minor parties to form the cabinet during the premiership of Katō Takaaki in 1924.

[9] During the 1932 General Election, buoyed by an upsurge in public opinion due to Japanese military successes in China, the Rikken Seiyukai won an overwhelming majority.

Inukai's efforts to limit further troop deployments to China and to defuse the Shanghai Incident through negotiations with the Chinese government drew increasing ire from the general public as well as the militarists.

The group chose twenty victims but succeeded in killing only two: former Finance Minister and head of the Rikken Minseitō, Junnosuke Inoue, and Director-General of Mitsui Holding Company, Dan Takuma.

Symbolically, Inukai withheld formal diplomatic recognition as a gesture of displeasure against the radical faction within the Imperial Japanese Army, and out of concern due to the rapidly worsening international relations with the United States, on which country Japan depended for much of its raw materials and capital investment.

[9] Inukai's struggle against the military led to his assassination during the May 15 Incident of 1932, which effectively marked the end of civilian political control over government decisions until after World War II.

Inukai's last words were roughly: If we could talk, you would understand (話せば分かる, hanaseba wakaru) to which his killers replied Dialogue is useless (問答無用, mondō muyō).

The original assassination plan had included killing the English film star Charlie Chaplin – who had arrived in Japan on 14 May and was Inukai's guest – in the hope that this would provoke a war with the United States.