Takashi Rinoie entered Kobe Shipyard of Mitsubishi Heavy Industries Company (1918). He made official tours of Europe and America (1935) and then became vice-chief of the same shipyard (1943). Rinoie assumed additional posts of vice-director of Kyoto Machinery Plant and Kyoto Motor Plant (1944). Then he appointed director and vice-chief of Yokohama Shipyard (1946) and president of the company, permanent director of Nikkeiren (Federation of Japan Employers' Associations) and Keidanren (Federation of Economic Organizations) and director of Zosen Kogyokai ( Shipbuilding Industry Society) (1950).
He resigned as president and reappointed director when the company was renamed Mitsubishi Nihon Heavy Industries Company (1952). He became director of Meiji Gomu Seizosho (Meiji Rubber Manufactory) and counseior of Mitsubishi Seiko Kaisha (Mitsubishi Steel Company) (1953) and later was appointed director of the latter company. He held additional posts of vice-chairman of Yokohama Chamber of Commerce & Industry and Sangyo Kyoiku Shinko Chilokai (Central Society for Promotion of Education in Industry), councilor of Nihon Kogyo Kurabu (Japan Industry Club), vice-chairman of Kanta Employers' Association and director of Nihon Boekikai (Japan Foreign Trade Society).