[1] Nagachika first served the Saitō clan of Mino Province; however, after their Demise at Battle of Inabayama 1567, he became a retainer of Oda Nobunaga.

On February 19, 1570, Imai Sokyu sent urgent news that Akagi Nobuyasu defeated the army of Miyoshi clan in Awaji province along with Nagachika and Kawajiri Hidetaka.

In 1580, he took part to suppress the Echizen Ikkō-ikki, and was granted Ōno Castle by Nobunaga.

In 1582, on Honnoji Incident, Nagachika’s eldest son and heir, Kanamori Naganori, died along with Oda Nobutada in fighting at the Nijō Castle.

Following Nobunaga's death, in 1583, at Battle of Shizugatake, Nagachika at first sided with Shibata Katsuie.