Examining the rise and fall of a socially democratic Gotham between 1945 and 1985, my dissertation presents a multiracial history of American popular culture. "Syncopating Segregation" links two previously disparate domains of scholarship: studies of postwar urban segregation and cross-cultural mediation. I argue that African American, Latinx, queer, and ethnically white New York musicians served as mediators who sought to rethink and remap the spatial contours of a divided city. In doing so, my work presents a somewhat unfamiliar picture postwar urban life: it moves beyond narratives of cultural appropriation and differs from many historians who posit that rigid patterns of segregation turned cities into racial and ethnic battlegrounds. While acknowledging that cities created new forms of de jure segregation, I show how African American and Latinx New Yorkers spurred musical cross-pollination during an era of mounting racial and ethnic division. Over the course of five chapters, I explore how musicians facilitated cross-cultural exchange in mambo, doo-wop, psychedelic rock, disco, and hip-hop. Each chapter revolves around mediators who used music to bridge racialized boundaries; by creating and popularizing integrated performance spaces premised on racial interaction rather than isolation, artists disrupted—but did not destroy—patterns of segregation in New York. I maintain that they changed the rhythm of the city just as they syncopated their music with off-beat cadences. Dancing at mixed-race clubs allowed New Yorkers to momentarily escape their segregated day-to-day lives. The existence of these venues in a divided landscape speaks to mediators’ successes in syncopating segregation. Although my dissertation serves as one of the first historical studies of musical forms that have traditionally been the purview of record collectors and fans, it is more than a series of genre studies. Instead, I reconstruct a social history of interracial musical scenes in post-World War II New York. Unlike most urban historians, I draw on oral histories, bootleg concert recordings, and fan magazines, in addition to an array of municipal and scholarly archives.