(November 6, 1854 – March 6, 1932) was an American composer and conductor of the late Romantic era, known particularly for American military and patriotic marches. Because of his mastery of march composition and resultant prominence, he is known as "The March King." In public, he was typically referenced by his full name.

Sousa served in the U.S. Marine Corps, first from 1868 to 1875 as an apprentice musician, and then as the head of the Marine Band from 1880 to 1892; he was a Sergeant Major for most of his second period of Marine service and was a Warrant Officer at the time he resigned.

He volunteered to serve as a bandmaster in the U.S. Army during the Spanish–American War but was unable to serve due to illness.