In January 1924, Ugaki was appointed Army Minister by Prime Minister Keigo Kiyoura. He continued in this post in the Katō Takaaki and the first Reijirō Wakatsuki cabinets until April 1927. The political machinations of the Rikken Seiyukai political party and his mentor, Tanaka Giichi, were behind his appointment. Ugaki strove to protect the superior position of the Imperial Japanese Army in Japanese politics, fearing a loss of influence to the Imperial Japanese Navy, should the United States be judged "Hypothetical National Enemy No. 1". Ugaki's plans called for an Army of 50 divisions. Nevertheless, despite Ugaki's strenuous opposition, the Katō Takaaki cabinet continued with its fiscal retrenchment policy (from May 1925) and Ugaki was forced to eliminate four infantry divisions (the IJA 13th Division, IJA 15th Division, IJA 17th Division, and IJA 18th Division), which resulted in the release of approximately 2,000 commissioned officers. He was also forced to shorten the period of time conscripts served with the remaining divisions and to force many senior officers into early retirement. The fact that the monies saved by these policies were used to implement much-needed modernization of military equipment and training had little impact on Ugaki's extremely unpopularity within the Army, and in 1927 Ugaki accepted a posting as Governor-General of Korea from April 1927 rather than continue as Army Minister.