John Philip Sousa's position in American (and World) music is set in stone by now. Others have composed great marches (the English composer Edward Elgar with his four "Pomp and Circumstance Marches" for instance, two of which are memorable), and such major composers like Wagner and Mendelsohn. But Sousa remains the "March King". Like Johann Strauss the Younger, Alexander Scarlatti, and Scott Joplin, he is recalled for his domination of a single area of music: marches in this case, rather than waltzes, sonatas, or "rags". But this really does not explain why he remains the "March King". There is a sense of fun and spirit in Sousa's marches that transcend what a march is usually supposed to do.
Marches were originally meant for troops to walk in step either on a training field or on the battlefield (music was used until the end of the 19th Century to keep up the spirits of the soldiers, and even to help orchestrate the speed they were to fight at when running across the battlefield). Sousa came from a musical family (his father was a musician in the Marine Corps band). Sousa followed in his father's footsteps, but played several instruments and rose to be the bandmaster. He began composing pieces for the Marine Corps Band, such as "Semper Fidelis", "The Washington Post March", "Manhattan Beach", and he tried to expand his abilities into other fields. When he left the Marine Corps, he formed his own band, which he developed with a perfect balance of brass, stings, percussion, and woodwinds. His band would go around the world performing, not only his own pieces, but also other composers as well.
The movie does touch, once or twice, on Sousa's attempts to broaden his musical ability by doing Broadway shows (operettas). At the start Clifton Webb, as Sousa, does play the melody of "Semper Fidelis" for his wife Jenny (Ruth Hussey) as a tune to be sung. It doesn't quite work. He would do a successful operetta (which is still revived) called EL CAPITAN, which starred DeWolf Hopper (we hear an actor as Hopper singing a tune at a rehearsal during the movie). However, EL CAPITAN had a book by Charles Klein, a major dramatist of the 1890s - 1915 (he drowned in the Lusitania disaster). Klein was not a W. S. Gilbert, but his libretto was serviceable. Unfortunately Sousa never had another librettist/lyricist like Klein, and spent the rest of his career seeking his "Gilbert". As a result the leading operetta composer from the U.S. in Sousa's lifetime (and since) was Victor Herbert.
Sousa was talented in other ways too. He sometimes wrote clever lyrics to comic songs, such as "A Typical Song of Zanzibar". He wrote about five comic novels too. He designed the special marching tuba, the "Sousaphone" (which is shown in the film being designed by Webb and Robert Wagner). But it is the string of great marches that he left which are his great donation to our culture. The reason is more than just his gift for melodious music. He was a genius at composition and orchestration - probably the best orchestrator among the major American composers.
His best remembered march is the title march for this film: THE STARS AND STRIPES FOREVER. The film mentions how Sousa, on a trip for his health, was walking the deck of the liner at night and thought of the beat of the music. We hear Webb describing the moment (quoting a passage from Sousa's memoirs, MARCHING ALONG), and the film ends with the playing of the great march. The film does not mention that that Sousa also composed words to be sung to it (which occasionally still are sung). A few years ago, the U.S. Congress formally adopted THE STARS AND STRIPES FOREVER as the national march.
I have gone into a great deal of detail regarding Sousa and his career, for the movie (for a biography) skims a lot. His literary efforts are not dealt with, and the film ends (really) with the playing of THE STARS AND STRIPE FOREVER. That was in 1899. Sousa would live until 1932, and would be a public figure until then. He was still composing until the 1920s.
Webb had an extensive musical comedy career in the 1920s and 1930s (he was one of the stars in Irving Berlin's AS THOUSANDS CHEER, for example). But aside from an occasional tune he sings like "When I wore a Tulip" or a dance he does with Jeanne Craig in CHEAPER BY THE DOZEN, he never did a musical. STARS AND STRIPES FOREVER is his one "musical film". He is credible as Sousa, but the film never really goes deeply into the great man. The dramatic portions are handled by Robert Wagner and Deborah Paget as friends and lovers, whose love affair is twisted for awhile by the Spanish American War. The film is certainly watchable (the cast is game, and the music is first rate) but it is not a showcase for Webb's talents in musicals. Ironically he could have been in Vincent Minelli's THE BANDWAGON with Fred Astaire and Cyd Charisse, but opted for the lead as Sousa. Probably a bad decision - but it is hard to say. Every July 4th STARS AND STRIPES FOREVER is shown for it's great holiday music. What we lost in not seeing Webb opposite Astaire is not enough to prevent our still seeing Webb as the great maestro composer.