This study describes the link between level of implementation and outcomes from an intervention to increase afterschool programs' (ASPs) achievement of healthy eating and physical activity (HE-PA) Standards. Ten intervention ASPs implemented the Strategies-To-Enhance-Practice (STEPs), a multi-component, adaptive intervention framework identifying factors essential to meeting HE-PA Standards, while 10 control ASPs continued routine practice. All programs, intervention and control, were assigned a STEPs for HE-PA index score based on implementation. Mixed-effects linear regressions showed high implementation ASPs had the greatest percentage of boys and girls achieving 30 min of moderate-to-vigorous physical activity (47.3 and 29.3%), followed by low implementation ASPs (41.3 and 25.0%), and control ASPs (34.8 and 18.5%). For healthy eating, high/low implementation programs served fruits and vegetables an equivalent number of days, but more days than control programs (74.0 and 79.1% of days versus 14.2%). A similar pattern emerged for the percent of days sugar-sweetened foods and beverages were served, with high and low implementation programs serving sugar-sweetened foods (8.0 and 8.4% of days versus 52.2%), and beverages (8.7 and 2.9% of days versus 34.7%) equivalently, but less often than control programs. Differences in characteristics and implementation of STEPs for HE-PA between high/low implementers were also identified.