Dwight D. Eisenhower
After the Japanese attack on Pearl Harbor, Eisenhower was assigned to the General Staff in Washington, where he served until June 1942 with responsibility for creating the major war plans to defeat Japan and Germany. He was appointed Deputy Chief in charge of Pacific Defenses under the Chief of War Plans Division (WPD), General Leonard T. Gerow, and then succeeded Gerow as Chief of the War Plans Division. Next, he was appointed Assistant Chief of Staff in charge of the new Operations Division (which replaced WPD) under Chief of Staff General George C. Marshall, who spotted talent and promoted accordingly.

Q: Who was the Chief of Staff who promoted Eisenhower?
George C. Marshall