Nobumori was the son of Sakuma Nobuharu. He became one of Nobunaga's senior men, although he briefly supported Oda Nobuyuki in his abortive attempts at rebellion in 1557. He commanded troops at Anegawa and was one of the three Oda commanders sent to assist Tokugawa Ieyasu against Takeda Shingen in 1573. At the resulting Battle of Mikatagahara, he joined Takigawa Kazumasu in fleeing before the Takeda army. Nobumori and his son Jinkûo were heavily engaged in the siege of the Ishiyama Honganji from 1575 until 1580. Following the surrender of the Honganji, Nobunaga wrote a scathing letter to Sakuma, accusing him of both incompetence and negligence and ordering him to shave his head and give up his lands in Yamato. He and his son thus wandered as beggars, Nobumori evidently dying of starvation or disease sometime between late 1581 or early 1582 at or near Mt. Koya.
- Initial text from Samurai-Archives.com FWSeal & CEWest, 2005