After the fall of the Rokkaku clan in 1568 due to the invasion by Nobunaga ODA, Shigemochi became a ronin (a lordless samurai), but in around 1584 he took service with Nobukatsu ODA and then with Ujisato GAMO.
1568年、織田信長の侵攻で六角氏が滅亡した後は浪人となったが、1584年頃に織田信雄、そして蒲生氏郷に仕えた。