Lord of Ono Castle in Kaifu District, Owari Province. During the Kanie Castle campaign of June 1584, as Takigawa Kazumasu and Kuki Yoshitaka fought for Toyotomi Hideyoshi and captured neighboring forts one after another, Shigemasa held Ono Castle and refused to defect even after his mother was taken hostage, remaining loyal to Oda Nobukatsu and Tokugawa Ieyasu. After the Battle of Sekigahara, in 1603 he was granted 15,000 koku in Ushiku, Hitachi Province, becoming the first lord of Ushiku Domain.

Known for his unwavering loyalty even when his mother was held hostage. The tenacity with which he endured the siege is credited with leading to his later advancement under the Tokugawa regime.

His stand at Ono Castle is said to have helped the Oda-Tokugawa side hold its ground during the Kanie Castle campaign. His achievements were recognized, and his descendants continued as lords of Ushiku Domain until the Meiji Restoration.