This dissertation examines music's role in cinema in the early years of synchronized sound film in the United States and France. Working against the historical and technological determinism that often plagues narratives of the transition to sound, I investigate the myriad ways in which directors, producers, and composers approached the new technology. Films acted as artistic manifestoes on the new technology and its aesthetic potential as filmmakers experimented with the musical soundtrack. Through multi-site archival research and close analyses of films and their music, I point to the heterogeneity of film music practices during synchronized sound's nascent years, considering early sound films as sites of aesthetic contestation and negotiation. / Music