A prolific composer, Filmore wrote over 250 tunes and arranged orchestrations for hundreds more; he also published a great number of tunes under various pseudonyms. While best known for march music, he also wrote waltzes, fox-trots, hymns, and novelty numbers.
Fillmore was born in Cincinnati, Ohio. In his youth he mastered piano, guitar, violin, and flute -- as well as the slide trombone, which at first he played in secret, as his conservative religious father believed it an uncouth and sinful instrument. He entered the Cincinnati Conservatory of Music in 1901. After this he traveled around the United States as a circus bandmaster with his wife, and exotic dancer.
In the 1920s he was back in Cincinnati, directing the Shriners Temple Band, which he turned into one of the most virtuosic marching bands in the country.
Fillmore's best known marches include Americans We, Klaxon, Men of Ohio, and His Honor.
He wrote a series of fifteen novelty tunes featuring trombone smears called "The Trombone Family", including Miss Trombone, Sally Trombone, Lassus Trombone and Shoutin' Lisa Trombone. A number of these have a strong ragtime influence.
In 1938 he retired to Miami, Florida, but kept active in his later years organizing and rehearsing high school bands in south Florida.