The son of a Buddhist priest, he was born in Tokyo, studied philosophy and graduated at Waseda University. He worked as a journalist at the Mainichi Shimbun for a while. After he finished military service, he joined "Toyo Keizai Shimpo" and later he became its president in 1941. He wrote about Japanese financial policy and had arguments with Inoue Junnosuke. Ishibashi had a liberal political view and was one of the rare personalities who opposed Japan's colonialism. Instead, he advocated a Small Japan policy; the core opinion of his Small Japan policy was the abandonment of Manchuria and of the other countries which Japan had partly or wholly colonized, to refocus efforts on Japan's own economic and cultural development. After World War II he received some political offers. The Japan Socialist Party offered to make him a candidate. Ishibashi became the minister of Finance under the first cabinet of Shigeru Yoshida from 1946 to 1947. In 1947 he was purged and forced to resign after openly opposing US General MacArthur's policies. After his purge was repealed in 1951, he allied with Ichirō Hatoyama and joined the movement against Yoshida's cabinet. In 1953 Ishibashi was appointed to minister of Industry by Hatoyama who became the prime minister. In 1955 the Liberal Democratic Party was formed and Ishibashi joined it. When Hatoyama decided to retire in 1956, the LDP held a vote for their new president. At first Nobusuke Kishi was considered the most likely candidate, but Ishibashi allied himself with another candidate and won the election. Ishibashi was appointed as president of the LDP and became the prime minister of Japan. Ishibashi stated that the government should endeavor to set up diplomatic relations with the People's Republic of China and his policy was popular among the people. Unfortunately he became sick and gave up his office only two months later. After he resigned the post of prime minister and post of president of LDP, he visited China in 1963. He was known as a prominent figure among liberal politicians in the LDP. He opposed Kishi's politics on security, which seemed too militant to Ishibashi. Tanzan Ishibashi died on April 24, 1973