By World War I, with the birth of jazz, ragtime and new dance styles like the foxtrot and tango, Herbert reluctantly switched to writing musical comedies. These featured less elaborate ensembles and simpler songs for less classically trained singers than the European-style operettas that had dominated his earlier career. Herbert, during the last years of his career, was frequently asked to compose ballet music for the elaborate production numbers in Broadway revues and the shows of Irving Berlin and Jerome Kern, among others. He was also a contributor to the "Ziegfeld Follies" every year from 1917 to 1924.