A daimyo of Yamagata-han in the province of Dewa who fought for both Toyotomi Hideyoshi and Tokugawa Ieyasu. He fought Uesugi Kagekatsu as well as in the battle of Sekigahara in 1600 for Tokugawa alongside Date Masamune. His domain was expanded to 520,000 koku for his loyal service.

His son Mogami Iechika succeeded him upon his death of illness.