Community-based programs hold significant potential to prevent cardiovascular disease (CVD) risk in youth. We describe here the longitudinal change in several modifiable CVD risk factors after participation in up to 3 years of Fit2Play™, a park-based afterschool program. Children ages 6-15 years old (N = 2261, mean age 9.0 years, 50% Hispanic, 47% non-Hispanic black, 54% male) who participated in Fit2Play™ for either 1-3 school years between 2010 and 2016 had height, weight, 4-site skinfold thicknesses, systolic and diastolic blood pressure, the progressive aerobic cardiovascular endurance run test, and health/wellness knowledge and behavior scores collected at the beginning and end of the school year(s). Effects of length of Fit2Play™ participation on CVD outcomes were assessed via 2-level repeated measures analysis adjusted for child sociodemographics, park, area poverty, and year. Adjusted models showed overweight/obese children who participated in up to 3 years of Fit2Play™ had a mean reduction of 8 mm in skinfold thicknesses; almost 0.5 SD's in BMI z-score; 5 DBP %ile points; 17% reduction in probability of developing hypertension; and a mean increase of 6.4 PACER laps and 17% increase in health/wellness assessment compared to baseline. A dose-response trend was found for years of Fit2Play™ participation and improved CVD risk profile in participating youth. In conclusion, park-based afterschool programs that promote preventive CVD risk strategies can be an equitable, low-cost, high value tool for addressing our national epidemics of obesity, heart disease and diabetes and a rapidly changing healthcare system in need of evidence-based prevention programs.