Following the Boshin War, Sadakata joined the Imperial Japanese Army. In 1871, he was promoted to the rank of Major (shôsa). In conjunction with the Seikanron ("invasion of Korea") debate, Sadakata was dispatched to perform an inspection tour in Manchuria in 1872. He resigned from the Army the following year and returned to Kagoshima.
- Plaques on-site at Nanshû Cemetery, Kagoshima.