Sueo Ito grew up in Kurtistown, Hawaii, where he graduated from high school in 1937. By that time, he had spent 12 years attending Japanese language school, approximate to a middle school education in Japan. He continued his education at the University of Hawaii and graduated in 1943 with a degree in vocational agriculture.
In July 1944, the Army drafted him and he trained at Camp Hellerman. After three months, the Military Intelligence Service Language School (MISLS) called him to Fort Snelling, Minn. After his language training, he left the United States for Manila and worked for the Allied Translator and Interpreter Section (ATIS). The war ended and from Manila ATIS he moved to work for the Judge Advocate Office of the Army Forces Pacific (AFPAC) where he worked at the war crimes trial of General Tomoyuki Yamashita, the "Tiger of Manila and the Conqueror of Singapore." Although an informal poll of reporters covering the trial resulted in a unanimous not-guilty verdict, the court convicted and sentenced Yamashita to execution on the basis of his command responsibility. Ito also worked on the trial of General Masaharu Homma who received the same verdict.
From the Philippines, Ito left for Tokyo where he worked at Tokyo ATIS in the NYK Building. Again, he received orders to work at the Judge Advocate Office, this time for the 8th Army headquarters in Yokohama, and interpreted for various trials concerning the mistreatment of POWs by the Japanese military. In these trials, Sueo noticed how cultural differences resulted in misinterpretations. For example, Japanese thought acupuncture and moxibustion (yaito) as standard medical treatments during that time, but Americans considered them forms of abuse. The trials also accused Japanese soldiers of withholding food from POWs, but actually they received the same amount of food as the troops.
In July 1946, the Army discharged Ito and he quickly applied for a civil service job to continue interpreting. He worked on a variety of trials ranging from the smuggling of Saccharin from Shanghai into Japan to the court martial of a colonel who tried to smuggle gems from the Bank of Japan to the United States. Upon his return to the United States in 1950, Ito entered dentistry school, graduated in 1954, and practiced dentistry throughout his life.