Tojiro Okamoto graduated from Easton Commercial School in New York (1908).
Tojiro Okamoto served first with Toyo Menka Kaisha (Cotton Company) (1910-1926). Entered Toyota Boseki Kaisha (1926) and became its director (1932) and then managing director (1936). When that company was merged with Utsumi Spinning Company and a few other companies to form Chuo Boseki Kaisha (Spinning Company) became its managing director (1942) and then managing director of Toyota Sangyo Kaisha (Industrial Company) (1942). When Chuo Boseki Kaisha was merged into Toyota Jidosha Kogyo Kaisha (Motorcar Industry Company) resigned as managing director (1943). Became vice-president of Toyota Industrial Company (1946). Dissolved Toyota Industrial Company and founded Nisshin Tsusho Kaisha becoming its president (1948). Held various additional posts including those of president of Toa Real Estate Company and member of Export Council of International Trade & Industry Ministry.