Followed Hideyoshi's death in 1598, Katsumoto was appointed the chamberlain of the Toyotomi household. After the Sekigahara campaign 1600, he was with Toyotomi Hideyori, the only son and heir of Hideyoshi, Katsumoto sought to negotiate a compromise between Ieyasu, Toyotomi clan lost most of his territory which were under management of 'western daimyō', and hideyori was degraded to an ordinary daimyō, not a ruler of Japan.