School Improvement Grants (SIG) represent one type of governments’ capacity-building investment to spur sustainable changes in America’s persistently under-performing public schools. This study examines both short- and long-run effects of the first two cohorts of SIG schools from two states and two urban districts across the country. Using dynamic event analyses, we observe that SIG showed larger effects in the second and third years of the intervention than the first year on 3-8th grade student test scores—a pattern of gradually increase over the course the intervention. These positive effects are largely sustained three or four years after the funding ended. In high schools, the SIG effects on 4-year graduation rates were steadily increasing throughout the period of six or seven years after the initial start of the intervention. These patterns of SIG effects mostly apply to each of the four locations, but the magnitude of effects varies across locations, suggesting differential implementations. Moreover, SIG effects on students of color or low-socioeconomic students are similar to, and sometimes a bit larger than, the overall SIG effects. We also conduct a variety of sensitivity and robustness checks. Lastly, we discuss the policy implications of our findings on states’ continuing efforts of transforming public organizations and building their long-term capacity for better performance.