This pragmatic, real world study examined the effects of the All 4 Kids© intervention on preschoolers’ mastery of movement skills and determined whether the instruction had greater impact than natural development. Methods included a quasi-experimental intervention-comparison subsample of 379 children (COMPARISON) and a pretest-posttest design with convenience scale-up sampling of 2817 preschoolers (SCALE-UP). Children receiving education and dance instruction 3 times/week for 8 weeks were assessed using the Preschool Movement Assessment to evaluate skills pre and post intervention. Using repeated measures ANOVA, McNemar and Wilcoxon signed ranks tests, preschooler’s participation in the intervention resulted in greater improvement in 12 movement skills (F = 83.451, df = 1, p < 0.001, η 2 p = 0.555), balance (p = 0.028), hopping (t = −3.545, df = 112, p = 0.001) and crossing the midline (p < 0.001) than natural development (COMPARISON). In the SCALE-UP study, children significantly improved in all measures based on post-intervention scores. Significant differences were observed between Hispanic and non-Hispanic children for the 12-skills (b = −0.758, se = 0.161, p < 0.001) using hierarchical linear models; boys’ and girls’ scores were not differentially impacted by the intervention. Therefore, implementation of interventions focused on fundamental movement skill development have the potential to remediate secular motor skill decline in young children. (author abstract)