[1] After his father, Kaneoki, died, Kanetsugu killed his uncle Kimotsuki Kaneshu to become the head of the clan.
In 1533, he had his son Kimotsuki Yoshikane take over the clan and retired but still held onto most of the actual power.
Knowing that there was no turning back, Kanetsugu tried to divorce his wife who was of from the Shimazu clan, but she did not agree and declined the offer.
In 1566, the Shimazu clan massed its army and invaded again, capturing Kōyama Castle as well as most of Kimotsuki's domains.
The desperate Kanetsugu retired to a small castle near the Shibushi area and committed suicide.