In 1894, during the First Sino-Japanese War, he was assistant navigator on the converted passenger liner Saikyō-Maru, serving under the formidable Admiral Kabayama Sukenori during the Battle of the Yalu River.

After serving on Atago and Kaimon, Satō was promoted to lieutenant in 1897 and was appointed as chief gunnery officer on Chin'en in 1898.

After his return in February 1904, Satō was assigned as chief gunnery officer on Azuma, where he served during the Russo-Japanese War at the Battle off Ulsan.

Returning to Japan in August 1906, he was promoted to commander and served as an instructor at the Naval Gunnery School from 1907 to the end of 1909.

[2] On February 7, 1917 Satō was assigned command of the 2nd Special Squadron, a task force of Japanese destroyers deployed to Malta in the Mediterranean as part of Japan’s assistance to the Allied war effort under the Anglo-Japanese Alliance.

His forces escorted convoys of merchant vessels and troopships, and performed anti-submarine warfare duties.