After working with Hoschna, his works had given somewhat of a name for himself. Arthur Hammerstein asked Harbach in 1912 to write the lyrics to an operetta with Rudolf Friml, called "The Firefly". Victor Herbert was originally supposed to write the music, but he refused to work with the star of the show, Emma Trentini, because in his last show, she had refused to sing a song for the encore, and Herbert walked out refusing to ever work with her again. Hammerstein could not find anyone as talented as Herbert, but settled on the unknown Friml because of his classical training. The result was a huge success, and it would spell eleven more musicals, including "High Jinks" (1913) (which featured the song "All Aboard Dixieland" by Jack Yellen and George L. Cobb) and "Katinka" (1915). Most of the shows they wrote together ran for over 200 performances. In 1914, he contributed the libretto only to the Percy Wenrich musical "The Crinoline Girl".