Born in Burbank, California, Aiso was during World War II the director of the U.S. Army Military Intelligence Service Language School (MISLS) that trained mainly nisei Japanese-language experts necessary for the war effort in the Pacific theater. Aiso was also an Asian American pioneer in the legal profession, serving as a judge in California. He was the first Japanese American judge on the U.S. continent.
Aiso grew up in Hollywood where he attended school and was a brilliant student. From his youth, Aiso encountered racism. White barbers refused to cut his hair, and he recalled a day when he boarded a streetcar and sat next to a white woman who elbowed him and declared loudly, “No Jap is going to sit next to me!” White schoolmates at Grant Grammar School in Hollywood taunted Aiso
and other Asian Americans, bullied them, and called them names. At LeConte Junior High School, Aiso ran for and won the presidency of the student body, but white parents protested at mass meetings, saying: “No child of mine is going to be under a Jap” (Ichinokuchi, 5). Because of parental pressure, the principal gave in and suspended student government until after Aiso graduated.
At Hollywood High School, Aiso joined the Reserve Officers' Training Corps (ROTC) program and received military training. He distinguished himself on the school's debating team, and won an oratorical contest on the Constitution but the principal pressured him to decline the award because, he said, white parents would be angry if a Japanese American represented the school. Aiso graduated from high school at the age of 16, went to Japan to study the Japanese language for 10 months, and returned to enter Brown University, which had offered Aiso admission and a scholarship through the intervention of Japan's ambassador in Washington, D.C. He graduated with honors in economics and went on to Harvard Law School. He received his law degree in 1934.
After passing New York's bar examination, Aiso practiced law in New York City in a Wall Street firm. On the invitation of a Japanese banker, he went to Tokyo to study Japanese legal terminology. He secured a job in China, working for the British American Tobacco Company, and after three years, largely because of his hepatitis, Aiso returned to the United States. He was drafted into the army in December 1940, and was selected to join other nisei at the military's fledgling Japanese-language school. Because of the army's exclusion orders, the school moved from San Francisco, California, to Camp Savage, Minnesota, and when that camp became too small, the school moved to nearby Camp Snelling. The school expanded from Japanese-language instruction to the teaching of Chinese and Korean.
The army promoted Aiso from instructor to the director of the MISLS, and he earned the rank of major. The school reached its peak in October 1945, and its some 6,000 graduates translated enemy documents, maps, and battle plans, interrogated Japanese prisoners, and undertook intelligence work. After the war, they translated for the Occupation forces in Japan. Their work hastened the war's end, and facilitated Japan's transition to democracy. Aiso urged the U.S. Occupation government to stress educational reform and to provide wage labor for the ordinary man “to earn, as a free man, a decent living for himself and his family” (Ichinokuchi, 21).
After his return from military duty in 1947, Aiso practiced law in California, and in 1952 was appointed commissioner of the Los Angeles superior court. A year later, he became a judge of the Los Angeles municipal court, and then, of the Los Angeles county superior court. In 1968, California's governor appointed Aiso an associate justice to the California court of appeals for the second appellate district where he remained until his retirement in 1972.
Japan's government decorated Aiso with its Third Class Order of the Rising Sun in 1984, and the following year at the awards banquet, Aiso thanked the Japanese government for the honor and said: “We Nisei and our offspring are making our contributions as American citizens to the political experiment which is the United States of America. For our unique position in Japanese-American and
world history, we Nisei are indebted as no other generation to our Issei parents who migrated from Japan to the United States. They were imbued with adventurous aspirations and permeated with the integrity of character so characteristic of heritage from such parents, which we have found to be an indispensable factor in making us exemplary American citizens” (Ichinokuchi, 27–28).
Aiso died in 1987 at the hands of a mugger.
Ichinokuchi, Tad. John Aiso and the M.I.S.: Japanese American Soldiers in the Military Intelligence Service, World War II. Los Angeles: MIS Club of Southern California, 1988.