Hyakutake graduated in the 30th class of the Imperial Japanese Naval Academy in 1902 and was appointed an ensign the following year.

Hyakutake spoke out strongly against this trend in his lectures at the Naval Staff College, emphasizing the importance of continued cooperation with the United States.

Tama was assigned as escort to HMS Renown (1916) during its visit with the Prince of Wales to Japan, and collided with a collier off Shimonoseki.

Hyakutake transferred command to the cruiser Kasuga in March 1923, and joined the Imperial Japanese Navy General Staff in December of the same year.

In February 1925, Hyakutake was sent as a naval attache to France and in June of the same year was part of Japan's delegation to the League of Nations.

On his return, he continued to teach at the Naval Staff College, continuing to promote the concepts of disarmament, external cooperation and negotiations and thus coming increasingly into conflict with the militaristic ultra-nationalism of General Sadao Araki and members of the Imperial Japanese Army's Imperial Way Faction.