Major philanthropic initiatives that incorporate features of venture-capital practices have become increasingly prominent, particularly in K-12 public education. In this study, we provide empirical evidence on the reach, character, and impact of the Broad Superintendents Academy, a prominent and controversial venture-philanthropic initiative designed to transform leadership in the nation's largest school districts. Using a novel dataset on all Broad trainees and a linked panel data set of all large school districts over 20 years, we find that Broad superintendents have had extensive reach (e.g., serving nearly 3 million students at their peak). We also show that, within districts that hired Broad trainees, Broad superintendents were 40 percent more likely to be Black than their non-Broad peers, but also had tenures that were 18 percent shorter. Panel-based estimates provide evidence that Broad-trained leaders had no clear effects on several district outcomes such as enrollment, school closures, per-pupil instructional and support-service spending, and student completion rates. However, Broad-trained leaders initiate a trend towards an increased number of charter schools and higher charter-school enrollment.