Hironaka Kataaki served as a bushō during the Sengoku period.  He was a retainer of the Ōuchi clan based in Suō and Nagato provinces.  Later, he became a retainer of the Mōri clan.

Kataaki was born as the second son of Hironaka Okikatsu.  Kataaki supported his older brother, Hironaka Takakane, the deputy military governor of Aki Province, and commanded naval forces from Iwakuni in the Ōshima District of Suō.  Together with Reizei Takatoyo and Kobayakawa Takakage (the third son of Mōri Motonari), Kataaki was responsible for one wing of the Ōuchi navy, serving valorously during the Kannabe Conflict and other battles.

In 1555, at the Battle of Itsukushima, his older brother (Takakane) and nephew (Hironaka Takasuke) sailed to Itsukushima and were killed in action.  Kataaki remained behind to oversee the territory of Iwakuni.  Later that year, during the offensive by the Mōri army known as the Subjugation of Bōchō, Kataaki did not resist.  Instead, he surrendered to Mōro Motonari in Iwakuni and entered the priesthood at the Kōhaku Temple, adopting the monk’s name of Sanzōsu.  In recognition of Kataaki’s abilities, Motonari engaged him as a retainer of the Mōri.  Kataaki received one of the characters from the name of Motonari, changed his name to Hironaka Nariyasu, and received a stipend of 300 kan.  Thereafter, as a member of the Mōri navy, Nariyasu primarily served under Kikkawa Motoharu (Motonari’s second son) and made contributions at the Siege of Moji Castle, the Siege of Tachibanayama Castle, and other conflicts.

His descendants continued as retainers of the Chōshū domain.