Research, nonprofit, and philanthropic organizations have increasingly had a larger influence in public educational institutions as they support particular programs, practices, and policy reforms. This study investigates the case of local organizations that have initiated and institutionalized high school dropout prediction systems called ninth grade early warning indicators (EWIs), and the strategies these entrepreneurial organizations used in spreading the innovation beyond the school districts they worked in. Situated in Chicago, Philadelphia, and New York City—districts that pioneered EWIs at scale—this research uses in-depth interviews and document analysis to trace the role of this “exoskeleton” of outside organizations in spreading EWIs not only in the cities they were in but also beyond them. With interviews from 73 organizational actors and 22 school staff, the study illustrates the role of entrepreneurial outsiders’ agency in influencing structures and cultures promoting human development outcomes, particularly in urban areas with large economically and racially minoritized populations. The research theorizes the urban spread of innovation, where improvements in a decentralized and disjointed system like the United States’ public education system, spread less through top-down policy mandates or bottom-up social movements, and more through the influence of “outside” organizations locally connected with various actors in the public school system and interconnected across urban school districts. The case of EWIs in the three cities illustrates the multi-level strategies employed by these organizations. At the macro-level, research and philanthropic organizations working with school district officials were able to bring together various institutional logics to frame EWIs that satisfy different educational stakeholders. At the meso-level, local state and non-state organizations—what many scholars consider as institutional entrepreneurs—were connected as each organization had unique contributions and niches in spreading the EWI innovation. At the micro-level, school support nonprofits worked directly in schools and with school leaders and teachers to change organizational routines and address resistance on the ground. But these local organizations were not just limited to working in the three cities. These local organizations became influential in spreading EWIs across the United States as the cities became proofs of concept for other districts, as organizations were contracted to work in other places, and as national institutions like the Institute for Educational Sciences and Gates Foundation supported these efforts. This dissertation expands and furthers the study of educational sociology, institutional change, innovation diffusion, and human development. For the sociology of education, this research highlights the enlarged role of “outside” organizations in influencing educational policies and practices. For the study of institutional change, this research integrates literatures on institutional logics, entrepreneurs, and routines in order to suggest a multi-level conception of the strategies employed to bring about institutional challengers’ intentional change. For innovation diffusion, this research emphasizes the less theorized spatial aspect of how innovations spread through the connections of organizations across various local systems. Finally, for the study of human development, this research highlights how “distal” organizational structures and systems interact with “proximal” implementers to bring about positive growth and development among disadvantaged and minoritized students.