ニュージョージア島の戦い
Peck was subsequently relieved by Colonel Samuel L. Howard on May 13, 1941, and returned to Washington, D.C., where he was attached to the staff of the commander in chief, United States Fleet, Admiral Ernest King. He was directly assigned to the War Plans Division of that command and served under Richmond K. Turner until May 1942. Meanwhile, he was promoted to the rank of brigadier general in March 1942. Peck was subsequently transferred to the Southern Pacific theater and assigned as assistant chief of staff for war plans to the South Pacific area Commander, Vice Admiral Robert L. Ghormley. Admiral Ghormley was relieved by William Halsey Jr. in October 1942, and Peck remained on his staff. He subsequently participated in the planning of the allied advanced to the Central Solomon Islands for the upcoming New Georgia Campaign and flew from Pacific to Washington, D.C., in January 1943 to present the outline of the operation.