In 1940, Sherman joined the War Plans Division, drafting plans for hemispheric defense, serving on the U.S.-Canadian Permanent Joint Board of Defense, and attending the August 1941 Atlantic Charter conference. Promoted to captain, in May 1942 Sherman assumed command of the aircraft carrier Wasp, but he lost his ship to the Japanese submarine I-19 on 15 September 1942 during the Battle of Guadalcanal, winning the Navy Cross for "extraordinary heroism."
Sherman then spent a year at Pearl Harbor as chief of staff to Vice Admiral John H. Towers, commander of the Pacific Fleet's air elements. His talent for staff work, including operational planning, force deployment, and logistical support, caused Admiral Chester W. Nimitz, commander U.S. Forces, Pacific Ocean Area, to appoint Sherman his planning officer as a rear admiral. As deputy chief of staff (plans), Sherman devised and implemented much of Nimitz's strategy in the Pacific Theater, including which specific islands would be attacked or bypassed. He also sometimes represented Nimitz, always ably, before the Joint Chiefs of Staff in Washington. He stood beside Nimitz and Admiral William Halsey at the Japanese surrender ceremonies of September 1945.
Returning to Washington, Sherman was promoted to vice admiral in December 1945. As deputy chief of naval operations, he became heavily involved in formulating both unification of the armed forces and Cold War strategy. After emphasizing to President Harry S Truman the potential Soviet threat in the Mediterranean, an important influence in the formulation of the Truman Doctrine of February 1947, Sherman became the first commander of the new U.S. Naval Forces, Mediterranean. In November 1949, Sherman became chief of naval operations as a full admiral. He supported U.S. intervention in the Korean War and proposed the successful naval blockade of North Korea. He also gave cautious approval to the September 1950 Inchon landing and backed Truman in his relief of general of the army Douglas MacArthur and the primacy of Europe in U.S. defense planning. While on a diplomatic assignment to Naples, Italy, Sherman suffered a fatal heart attack on 22 July 1951. Priscilla Roberts
Barlow, Jeffrey G. Revolt of the Admirals: The Fight for Naval Aviation, 1945–1950. Washington, DC: Naval Historical Center, 1994.; Hoyt, Edwin P. How They Won the War in the Pacific: Nimitz and His Admirals. New York: Weybright and Talley, 1970.; Reynolds, Clark G. The Fast Carriers: The Forging of an Air Navy. Annapolis, MD: Naval Institute Press, 1968.; Reynolds, Clark G. Famous American Admirals. New York: Van Nostrand Reinhold, 1978.; Reynolds, Clark G. "Forrest Percival Sherman, 2 November 1949–22 July 1951." The Chiefs of Naval Operations, 209–232. Ed. Robert W. Love, Jr. Annapolis, MD: Naval Institute Press, 1980.