Purpose: Nearly all schools in the United States closed in spring 2020, at the onset of the COVID-19 pandemic. We analyze traditional public and charter school reopenings for the 2020-21 school year in five urban districts. We provide a rich and theoretically grounded description of how and why educational leaders made reopening decisions in each of our case districts. Research Methods: We used data from a multiple-case study from March 2020 to July 2021. The research team conducted 56 interviews with school, district, and system-level leaders; triangulated with publicly available data; and also drew on interview data from a subsample of parents and guardians in each of our sites. We analyzed these data through qualitative coding and memo writing, and conducted detailed single- and cross-case analyses. Findings: School system leaders in our case sites generally consulted public health authorities, accounted for state-level health and educational guidance, and engaged with and were responsive to the interests of different stakeholders. Districts' adherence to and strategic uses of public health guidance, as well as a combination of union-district relations and labor market dynamics, influenced reopening. Parents, city and state lawmakers, and local institutional conditions also played a role, helping to explain differences across cases. Implications: In contrast to the "politics or science" framing that has dominated research and public discourse on school reopening, we show that local pandemic conditions and local political dynamics both mattered and in fact were interrelated. Our findings have some implications for how educational leaders might navigate future crises.