In 1967 Mark Tanaka joined the mainframe computer design group at Toshiba Corporation. After his position there, he was assigned to the General Management position at Toshiba America where he was in charge of notebook PC's sales there in the late 1980's. Upon his return to Toshiba Headquarters, he was responsible for European and Oceania PC sales leading to the top worldwide share of Toshiba PC's in the world.

In 1993 he left Toshiba to join Sun Microsytems, Inc. to head up their software operations in Japan. He was instrumental in the sales and licensing of Sun software products in Japan including Solaris and Java. He established the Java Initiative in Japan which eventually led to the proliferation of Java in the Japanese marketplace.

In 1998 he joined Citrix Corporation, becoming the president of Citrix Japan. He initiated the penetration of MetaFrame into the Japanese marketplace, and quickly grew the business to an annual revenue of over US $30 million. He introduced the ASP (Application Service Provider) business model to the Japanese marketplace, and contributed to the establishment and activities of the ASP consortium there.  He is currently still active in the establishment of the Mobile Enterprise Alliance in Japan.

In his spare time, Mark enjoys golf, scuba diving, and bird watching.