Eldest son of Tadanori Ishiguro. He graduated from the Law College of the Imperial University of Tokyo in 1908 and joined the Ministry of Agriculture and Commerce. He served as the director-general of the Agricultural Affairs Bureau, director-general of the Silk Bureau before becoming the Vice-Minister of Agriculture and Forestry in 1931. After leaving his office in 1934, he held important posts in agricultural organizations such as the president of the Noson Kosei Kyokai and the president of the Sangyo Kumiai Chuo Kinko (Industrial Cooperative Central Bank) among others. He was appointed the Minister of Agriculture and Forestry in the second Konoe Cabinet in 1940. He was selected as a member of the House of Peers in 1943. He served as the Agriculture and Commerce Minister in the Kantaro Suzuki Cabinet in 1945. He was purged from public office in 1946. After the termination of the purge in 1952, he was elected a member of the House of Councillor s and joined the Ryokufu-kai. He was called the "king of agricultural policy."