In the early twentieth century, the publishers of Tin Pan Alley revolutionized American music. Focused on the dissemination of a constantly changing set of attention-grabbing songs, leading companies dramatically expanded the market for popular compositions, generating hits that sold millions of copies of sheet music to customers across the country. While publishers aimed at this continental audience, their output was shaped by the urban context in which their businesses first emerged. During these years, local popularity was crucial to national success. As a result, firms sought to engage with new audiences throughout Manhattan, incorporating a host of social and ethnic groups into the structures of commercial entertainment. Over time, Tin Pan Alley’s relationship to these groups—and the distinctive leisure spaces in which they gathered—would define its musical production. It was not simply that publishers molded songs to fit public taste. Rather, the industry and the broader world of commercial entertainment developed together. By exploring this business-influenced process of cultural change, it is possible to gain new perspective on the emergence of American popular song, as well as the consumption-driven dynamics remaking society in the Progressive Era in the United States.