The Ishibashi clan ruled over the Shiomatsu region where this castle is located during the Muromachi period Ashikaga shogunate.

In 1568, Ōuchi Yoshitsuna overthrew his overlord, Ishibashi Naoyoshi, and declared the area to be independent.

In 1586, Ōuchi Sadatsuna fled to the Ashina territories and Masamune entered Obama Castle without battle.

The surviving stone wall at the present-day ruins of the main castle is from this time.

The Gamō were subsequently displaced by the Uesugi clan during which time Yamaura Kagekuni became castellan.