Mitchell was subsequently transferred to the Pacific, where relived Major general Roy S. Geiger from command of the 1st Marine Aircraft Wing on April 21, 1943. He was promoted to the rank of major general on the same date. He was also Commander Marine Aircraft, South Pacific. Mitchell commanded these units during initial stage of Rabaul operation and subsequently planned and coordinated air strikes against Japanese fortifications at Rabaul. In the upcoming Bougainville Campaign, general Mitchell successfully attacked the supply lines of enemy cargo ships. For his tireless effort Mitchell was decorated with the second Legion of Merit and Navy Distinguished Service Medal.