Motochika Chosokabe was born in 1539, the eldest son of the lord of Okojo Castle.
Having succeeded his father, who died a month after his first battle, over fifteen years Motochika first unified Tosa, then over ten years conquered most of Shikoku Island.
However, in August 1585 he surrendered to Hideyoshi Toyotomi, relinquishing control of Shikoku Island and retaining possession of only the Tosa province.

He later moved his castle to Urado and built a castle town.
On the 19th of May 1599, at the age of 61, he died at his residence in Fushimi.