From 1938 to 1941, Kinkaid was a naval attaché in Italy and Yugoslavia. In the months prior to U.S. entry into World War II, he commanded a destroyer squadron. Promoted to rear admiral in 1941, he assumed command of a U.S. Pacific Fleet cruiser division. His cruisers defended the aircraft carrier during the Battle of the Coral Sea and during the Battle of Midway. After that battle, he took command of Task Force 16, a task force built around the carrier , which he led during the long and difficult Solomon Islands campaign, participating in the Battles of the Eastern Solomons and the Santa Cruz Islands. Kinkaid was placed in charge of the North Pacific Force in January 1943 and commanded the operations that regained control of the Aleutian Islands. He was promoted to vice admiral in June 1943.