Akao Kiyotsuna served, together with Kaihō Tsunachika and Amenomori Kiyosada,  as one of an infamous triad of generals for the Azai clan. Kiyotsuna received the Court title of Mimasaka-no-kami, or Governor of Mimasaka. The term “kami” was designated the highest of a four-level rank for kokushi, or officials serving as local commissioners on behalf of the central authorities in Kyōto.

The Akao clan were kokujin in Ōmi Province, originally obeying orders of the Kyōgyoku and later the Azai.  Kiyotsuna served the Azai from the time of its first-generation lord, Azai Sukemasa.  As an especially trusted retainer, Kiyotsuna had a residence inside the grounds of Odani Castle serving as a key defense structure, referred to as “Akao’s Defense Quarters.”  Retainers typically resided in areas below the castle, so the location of Kiyotsuna’s quarters inside the castle reflected his elevated status in the clan.

In the era of Azai Hisamasa (Sukemasa’s son), Kiyotsuna plotted with Endō Naotsune to have Azai Nagamasa (Hisamasa’s son) take control of the clan and to force Hisamasa into retirement.  At a moment when Hisamasa was absent, Kiyotsuna and Naotsune took over the castle and compelled him to recognize Nagamasa as the new lord.  Given his age and experience, Hisamasa continued as an advisor in military affairs.

In conflicts between the Azai and the Rokkaku, Sukemasa had in the past fled to Echizen Province, and formed an alliance with the Asakura clan in an effort to stand-up to the Rokkaku. The goodwill between the Azai and the Asakura clans continued in the era of Nagamasa.  

On 9/1 of 1573, Kiyotsuna became a prisoner of the Oda in the Battle of Odani Castle and committed seppuku in front Nobunaga, sharing the same fate as Nagamasa. Meanwhile, Nobunaga granted clemency to Kiyotsuna’s son, Akao Kiyofuyu, in deference to the effort and loyalty demonstrated by Kiyotsuna.