Leonard Wood was a United States Army major general, physician, and public official. He served as the Chief of Staff of the United States Army, Military Governor of Cuba, and Governor-General of the Philippines. He began his military career as an army doctor on the frontier, where he received the Medal of Honor. During the Spanish–American War, he commanded the Rough Riders, with Theodore Roosevelt as his second-in-command. Wood was bypassed for a major command in World War I, but then became a prominent Republican Party leader and a leading candidate for the 1920 presidential nomination.

The chief of staff of the Army (CSA) is a statutory position in the United States Army held by a general officer. As the highest-ranking officer assigned to serve in the Department of the Army, the chief is the principal military advisor and a deputy to the secretary of the Army. In a separate capacity, the CSA is a member of the Joint Chiefs of Staff and, thereby, a military advisor to the National Security Council, the secretary of defense, and the president of the United States. The CSA is typically the highest-ranking officer on active duty in the U.S. Army unless the chairman or the vice chairman of the Joint Chiefs of Staff are Army officers.