This paper describes the crucial and complex role of Nisei (second-generation Japanese American) linguists (translators and interpreters) during the Pacific War and subsequent occupation of Japan. Most of these Nisei linguists were recruited by the US Army from among the nearly 120,000 Japanese and Japanese Americans forcibly relocated to internment camps after Japan’s attack on Pearl Harbor in December 1941. More than 6,000 Nisei linguists were sent to the Pacific theater to translate captured documents, break codes, and interrogate Japanese prisoners of war, while their families and friends were still detained in the camps. In postwar occupied Japan, Nisei linguists functioned as a bridge between the occupation forces and the Japanese authorities and civilians in addition to working as translators, interpreters and monitors in trials against Japanese war criminals. During the war, Nisei linguists constantly had to confront the language and people of their own heritage in hostile settings, while also fighting against the suspicion of disloyalty within the US Army. Further, they feared being caught, tortured and killed as traitors by Japanese soldiers. Drawing on Cronin’s notion (2002, 2006) of heteronomous and autonomous interpreters, this paper examines the complexity of Nisei linguists’ position as “in-between”. It also discusses issues of trust, control, and identity concerning military interpreters who use their language skills against people of their own cultural heritage.