Irobe Akinaga served as a bushō during the Sengoku period.  He was a retainer of the Uesugi clan and a member of the Agakita Group in Echigo Province.  Akinaga served as the lord of Hirabayashi Castle in the Iwafune District of Echigo.

In 1569, his father, Irobe Katsunaga, died during the Revolt of Honjō Shigenaga, upon which Akinaga inherited the headship of the clan.  He received the name of Akinaga from his lord, Uesugi Terutora (later known as Uesugi Kenshin).

Akinaga was not blessed with a strong constitution so, in 1576, he transferred the headship to his younger brother, Irobe Nagazane, and retired.