Born in Berkeley, California and raised in Salt Lake City, Utah, Ishio attended elementary and high schools in Salt Lake. After one year at the University of Utah, he went in 1939 to Tokyo with his grandparents -- his grandfather was returning to Japan following retirement from the railroads -- to matriculate in the Economics Department of Waseda University. He completed two years of schooling and then returned home in 1941 after receiving a warning from the American Embassy about worsening relationships between Japan and the United States. (He finished his undergraduate education at Georgetown University after the war on the GI Bill, and also completed two years of graduate study, in linguistics and languages.)

Drafted in 1941, he was placed in the Special Class of June 1942 at the MISLS, Camp Savage. He was assigned to I Corps in September 1942 after graduation, and … saw action in the Papua and Buna campaigns, and after being promoted first to warrant officer and three months later to second lieutenant, participated in the Leyte campaign with the Sixth Army. Two members of his team, Spady Koyama and Cappy Harada, were wounded when their ship was hit. He was decorated with the Bronze Star and two unit citations.

Discharged in1947, Ishio joined the Central Intelligence Agency and remained with that agency until his retirement in 1973, serving on assignments in Tokyo and Saigon, and on an around-the-world inspection trip in 1956. He had continued to serve the Army as a reserve officer, first as CO of the CIA Pacific Division Unit and later CO, Mobilization Designation Detachment, Assistant Chief of Staff, Intelligence, in the Pentagon, retiring with the rank of colonel. He entered a second civilian career in 1973 on contract with the Drug Enforcement Adminstration as director of the Narcotics and Dangerous Drugs Information System until his final retirement in 1990.

Ishio is the founding president of the Japanese Americans Veterans Association of Washington, D.C., established in 1992 around a nucleus of MIS, 442nd, and other veterans, with the initial objective of organizing the MIS National Capital Reunion in October 1993.

Moreover, as president, he was able, with support from Senator Akaka's office, to have the Secretary of the Army approve the writing of an official Army history of the role of the Nisei in the Pacific and Asian theaters of war; to have an MIS exhibit set up with the backing of the National Historical Intelligence Museum in the Reserve Officers Building on Capitol Hill -- an exhibit to be moved later to the National War College and the Pentagon, and perhaps permanently to the MacArthur Memorial, Norfolk, Virginia; and to initiate talks with other MIS associations regarding the formation of a national MIS federation.