In 1919 or 1920, Cailliet emigrated to the US and joined the Philadelphia Orchestra,[5] as a clarinetist, saxophonist, and staff arranger, where he worked closely with Leopold Stokowski.
Cailliet served as Associate Conductor of The Allentown Band (Pennsylvania) beginning in 1934,[6] during which time he conducted many of his own arrangements.
His arrangements of Elsa's Procession to the Cathedral (from Wagner's opera Lohengrin) and Finlandia (a symphonic poem by Jean Sibelius) have become staples of the wind ensemble repertory.
Among the best known of these films are She Wore a Yellow Ribbon, The Ten Commandments (for which Elmer Bernstein wrote the score), and Gunfight at the O.K.
His most famous orchestration is the virtuoso piece for piano and orchestra Midnight on the Cliffs by the pianist and composer Leonard Pennario, for the Andrew L. Stone film Julie (1956).