The March King John Philip Sousa was an American composer and conductor of the late 19th and early 20th centuries. He is known for his military marches, which earned him the nickname 'The March King'. He composed over 130 marches, including 'The Stars and Stripes Forever', which is the official march of the United States of America. He also wrote many other pieces of music, including waltzes, galops, and operettas.