Philanthropic initiatives incorporating prescriptive practices have become prominent in K-12 education. This study provides evidence on the reach, character, and impact of the Broad Superintendents Academy, a controversial initiative designed to transform district leadership. A novel data set on Broad trainees linked to data on large districts over 20 years shows that Broad superintendents have had extensive reach, serving nearly 3 million students at their peak, and that, for districts that hired Broad trainees, Broad superintendents were 40% more likely to be Black than non-Broad superintendents, although they had significantly shorter tenures. Estimates provide evidence that Broad-trained leaders had little effect on several district outcomes including enrollment, spending, and student completion. However, they initiated a trend toward increased charter school enrollment.