This chapter explores the sustainability of “free-market diversity” in urban education—diversity based upon individual choices rather than explicit policies. Based upon follow-up research, the chapter outlines the demographic shifts at the school over a four-year period as well as how parents and school staff interpreted and responded to the material and demographic change occurring at the school. The chapter argues that schools like Morningside that become more socioeconomically and racially diverse through neighborhood demographic shifts and middle-class parent engagement are unlikely to sustain their diversity over time in the absence of dedicated resources and explicit education policy. The research suggests that the investments of middle-class parents in urban public schools, in concert with school and district integration policies that ensure that these schools remain accessible to low-income students, may help to disrupt entrenched patterns of segregation, resource disparity, and inequity in public districts and schools.