Morishige was a son of Date Harumune and was adopted by Kokuban Noto no kami Moriuji. He distinguished himself at the Battle of Hitadori Bridge under Date Masamune (1585). In 1590, when Masamune submitted to Toyotomi Hideyoshi, Morishige went as a hostage and was placed in the custody of Gamô Ujisato. In 1599 Masamune came to doubt Morishige's loyalty and decided to have him assassinated. Morishige learned of the peril he was in and fled the Date domain, finding service with the Satake clan and thereafter living in Yokote castle.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005