Born in 1279, from the Akahashi branch of the Hojo—a great-grandson of Hojo Yoshitoki through the line of Yoshitoki's son Shigetoki. The Akahashi branch would later produce the last regent Hojo Moritoki and Ashikaga Takauji's principal wife Akahashi Toko. Hirotoki built experience through key shogunate posts including the hyojoshu and as rensho. He became twelfth regent following a period of confusion in 1311 when both the tenth regent Morotoki and ninth tokuso Sadatoki died in the same year, and the eleventh regent Munenobu then resigned after only a brief term. By this time the tokuso's authority was beginning to waver and the uchikanrei Nagasaki family was exerting growing influence over governance. Hirotoki conscientiously performed his duties as regent in these difficult late-Kamakura circumstances, working to maintain administrative continuity. He died in 1315 at 36 and was succeeded as the thirteenth regent by Hojo Mototoki, also of the Akahashi branch. A figure who steadily fulfilled his responsibilities through the Akahashi line's continuity during a period of power transition near the shogunate's end.

He fulfilled his duties in the difficult final period of the shogunate. Even in the difficult situation of declining authority of the Toku house, he discharged his responsibilities as regent.

He held the regency in the shogunate's final period and served as a bridge to the next generation.