Toshio Nishi is a research fellow at the Hoover Institution.

From 1991 to the present, Nishi has been a distinguished guest professor at Reitaku University in Chiba, Japan, and from 2004 a graduate school professor at Nihon University in Tokyo.

From 1968 to 1971, Nishi worked for J. Walter Thomson Company in New York and Tokyo as the first Japanese account representative.

From 1977 to 1991, Nishi was a postdoctoral fellow at Hoover Institution as the first recipient of the Paul and Jean Hanna Endowment Fellowship. From 1985 to 1991, Nishi was a foreign correspondent for NHK Journal, a radio program of Japan's largest media system.

Nishi has written extensively on the U.S. military occupation of defeated Japan and contemporary Japan and Asia. His representative book in English is Unconditional Democracy: Education and Politics in Occupied Japan, 1945–1952 (Hoover Institution Press, 1982; reissued in 2003). His books in Japanese are Nichibei Konryokusen (Battle over Japan's Soul, Tokyo: Chuo Koron-shinsha, July 2003, 2nd printing), Kuniyaburete MacArthur (The Invasion of MacArthur, Tokyo: Chuo Koron-shinsha, 1996, 6th printing, best-seller), Fukoku Jakumin: Nippon (Wealthy Nation, Weak People: Japan, Reitaku University Press, 1996, 5th printing, best-seller), and MacArthur no Hanzai (The "Crime" of MacArthur, Tokyo: Otemachi Books, 1983).

Nishi is currently working on several manuscripts: Japan's Last Stand in the 21st Century (in English), Hearts of the Empire (fiction in English), and an article entitled "Holy Ghost, Divine Greed, Slow Massacre: The Europeans in the 16th Century Japan."

Nishi has been one of the most sought-after speakers on Japan's national speaking circuit. He has been a member of the board of regents of Executive Forum of Japan since 2000. From 1997 to 1999, Nishi was a commentator for TV Tokyo. Nishi is chairman of the editorial board and a monthly columnist for Kokkai News (a news magazine on politics), Japan's oldest monthly magazine.

Nishi has been awarded many scholarships and grants. From 1977 to 1985, he received a postdoctoral fellowship from the Hoover Institution. In 1977 he also received the prestigious Harry S. Truman Scholarship from the Harry S. Truman Library Institute in Missouri, and the Douglas MacArthur scholarship in Norfolk, Virginia.

After earning a BA in Literature from Kwansei Gakuin University in Japan in 1964, Nishi received his MA in communications in 1968 and his PhD in political studies of education in 1976 from the University of Washington at Seattle.