Sousa studied music at a local conservatory, and when he was 13 his father got him a job as an apprentice musician with the Marine Band.
Then, as now, no direct military training was required for Marine Band musicians, Ressler said.
Hamilton Thomas Abert, 4, stands on his great-great-grandfather's grave while he waits for the U.S. Marine Band to arrive.
(Bill O'leary -- The Washington Post)
"The logic then was the same as it is now," he said. "They are fully trained to do what they were brought into the Marine Corps to do: a very specialized and unique job, with no other specific responsibilities."
Sousa became a full-fledged member of the band at age 17 and stayed until he was 20. He then went out on his own for several years, but in 1880 he was invited back to Washington to become the Marine Band director.
He accepted, and over the next 12 years he transformed the band and American music.
He left the Marines again in 1892 but organized his own bands and continued writing and performing through the first three decades of the 20th century.
All during his career, he wrote music. He wrote songs, operettas, suites, waltzes and dances, according to Marine Band records.
He also wrote three novels, an autobiography and, perhaps most famously, his 137 marches.
He wrote "The Stars and Stripes Forever," by law the nation's official march, in 1896. He wrote his famous salute to the Marine Corps, "Semper Fidelis," in 1888.
He wrote "The Washington Post" for the June 15, 1889, awards ceremony of a children's essay contest sponsored by this newspaper.
Sousa wrote marches in honor of the Boy Scouts, the Liberty Bell, Mother Goose and the Salvation Army.
He wrote a march for President James A. Garfield's inauguration in 1881 and one for the president's funeral after he was assassinated a few months later.
He wrote a patriotic World War I march, "The Volunteers," in 1918 with imitation shipyard sounds that included an ear-splitting, simulated rivet gun.
Sousa died, probably of a heart attack, on March 6, 1932, at the Abraham Lincoln Hotel in Reading, Pa., where he was to conduct the town's band. He was 77.
His body, clad in a Navy uniform, was brought to Washington and lay in state in the Marine Barracks, where he had practiced as a boy.
And as they carried his body out to the cemetery, past the crowds that lined the streets, Ressler said, the Marine Band played "Semper Fidelis" in dirge time.