John Fujio Aiso (December 14, 1909 – December 1987) was an American Nisei military leader, lawyer, and judge.
Aiso graduated from Harvard Law School in 1934. Between 1935 and 1952 Aiso worked in private practice in Los Angeles and New York. Aiso was the highest-ranking Japanese American in the United States Army during Second World War, reaching the rank of Lieutenant Colonel. Returning to the United States after working for a British company in Japanese-occupied Manchuria, he was conscripted into the Army and within months he was released from active duty to serve as chief instructor for the hastily-formed secret Japanese language school. Under his inspiring leadership as director of academic training, MISLS (Military Intelligence Service Language School) rapidly expanded. He recruited instructors and trained them, developed course materials, and set the highest academic standards. The more than 6,000 graduates contributed immeasurably to the American victory over Imperial Japan and to wining the peace that followed. In 1946, he was given a direct commission as Major and awarded the Legion of Merit in 1947. In 1952, he served as a Commissioner for one year. He was then appointed to the Los Angeles Municipal Court in 1953 and later elevated to the Los Angeles Superior Court. He became the first Japanese-American to enter the California State Judiciary. Aiso became an Associate Justice of the California Court of Appeal, Second Appellate District on November 4, 1968.
President Lyndon B. Johnson awarded him the Legion of Merit in 1965 for his service during World War II. In 1984, the Emperor of Japan awarded him the 3rd Class Order of the Rising Sun for his contributions to understanding and friendship between the United States and Japan. He was inducted into the Military Intelligence Corp Hall of Fame in 1991. The Aiso Library at the Defense Language Institute (DLI) Foreign Language Center is named in his honor for his contributions as the chief instructor of what became the Military Intelligence Service Language School, the predecessor of DLI. In the Little Tokyo community of Los Angeles, a one block segment of San Pedro St. between Temple Blvd. and 1st Street has been renamed Judge John F. Aiso Street in his honor.