As of 2007, ORIX was Japan's largest leasing and leading diversified financial services conglomerate with assets in excess of US$69 billion and subsidiaries & associates in 24 countries worldwide.

[3] Upon completing his MBA, Miyauchi returned to Japan and in 1964 joined a small startup, Orient Leasing Co. Ltd., that helped pioneer the lease financing of machinery and industrial equipment for Japan's booming manufacturing base.

Now known as ORIX Corporation, the company expanded rapidly during the 1960s and '70s, diversifying the range of its products and services to include ships and aircraft, along with real estate finance and development.

[5] In addition to being one of Japan's top corporate leaders, Miyauchi is a strong advocate of regulatory reform and served as president of the Council for Promoting Regulatory Reform, an advisory board to the prime minister of Japan.

[5] He serves as a director on the boards of many major corporations including Fuji Xerox, Showa Shell Sekiyu and Sony.