Ohga served as consultant and advisor to Tokyo Tsushin Kogyo (renamed SonyCorp. in 1958) during the development of Japan's first tape recorder. In 1959, he was named general manager of Sony's Tape Recorder Division. He concurrently served as head of Sony'sProduct Planning Division, and was simultaneously in charge of Industrial Design at Sony. In the 1960s, Ohga’s goal was to make easy-to-use tape recorders available to everyone. Ohga chose the Philips compact cassette and convinced the company to make the technology available free of charge to manufacturers worldwide to make the cassette a global standard.
In 1968, Ohga was appointed senior managing director and representative director of the joint venture between CBS Inc. and >Sony Corp. (CBS/Sony Group Inc.–now called Sony Music Entertainment Japan Inc.). Ohga also played a key role in the establishment of new audio formats, such as the compact disc (CD) in 1982, the MiniDisc (MD) in 1992, and Super Audio CD (SACD). Appointed chairman and CEO of Sony Corp. in 1995, he became chairman of Sony Corp, effective July 1999. Ohga has been celebrated for his distinguished work as a conductor of symphony orchestras worldwide. The Audio Engineering Society (AES) awarded an honorary membership to recognize Ohga's lifetime technical, artistic and business contributions to the audio industry.