This study aimed to evaluate a multicomponent, child-appropriate preschool intervention program led by preschool teachers to enhance physical activity (PA) and motor skill performance (MS) in 4- and 5-yr-old children. Methods: Evaluation involved 709 children (mean age, 4.7 +/- 0.6 yr; 49.5% girls) from 41 preschools (intervention group, n = 21; control group, n = 20) in the rural and urban surroundings of two German cities. Children in the intervention group received a daily PA intervention lasting 30 min and PA homework over one academic year, which was designed by professionals but led by preschool teachers. The intervention included educational components for parents and teachers. Primary outcomes were MS (composite MS score) and objectively measured moderate-to-vigorous PA (MVPA) by accelerometry. Measurements were performed at baseline, midintervention, and postintervention as well as 2-4 months after the end of intervention. Intervention effects were analyzed by repeated measurement analysis adjusted for group, sex, age, baseline outcomes, urban/rural location of the preschool, and cluster (preschool). Results: Compared with controls, children in the intervention group showed positive effects in MS at postintervention (estimate effect, 0.625 z-score points; 95% confidence interval (CI), 0.276-0.975; P = 0.001) and at follow-up (estimate effect, 0.590 z-score points; 95% CI, 0.109-1.011; P = 0.007) and an increase in MVPA from baseline to postintervention by 0.5% of total wearing time (95% CI, 0.002%-1.01%; P = 0.049) at borderline significance. There was no benefit on MVPA for the intervention group between baseline and follow-up. Conclusions: A child-appropriate, multidimensional PA intervention could sustainably improve MS but not PA. Findings suggest that a change in health-related behaviors is difficult. Future research should implement participatory intervention components in preschool setting and better integrate the families of the children. (author abstract)