In 1941, Gunther Rothenberg volunteered for the British army, serving in an all-Jewish unit. He was wounded in North Africa. He transferred from the Royal Army Service Corps to the Intelligence Corps and fought with the Eighth Army. He served in the Italian campaign, in the Yugoslav war of liberation and in Austria. His service continued in the occupation of Austria until 1946. He was a civilian employee of U.S. Intelligence 1946–1948. Rothenberg returned to Palestine and joined the Haganah for 1948 Palestine war. He rose to the rank of captain in the Israel Defense Forces.