Objective: The Healthy Environment Project (HEP) was designed to improve familiarity with attitudes, confidence and knowledge related to health-promoting best practices, as well as the implementation of health-promoting policy, system and environment best practice change in diverse early childhood education settings. Design: Pre-post study design to assess the outcomes of the HEP intervention. Setting: Early childhood education providers representing 14 centres (n = 117) and 30 homes (n = 30) in Colorado, USA. Method: The Policy, System and Environment Change Process, which is an evidence-based strategic planning process based on intervention mapping, was facilitated in a professional development training format in 44 early childhood education settings. Results: Pre-post survey data (n = 125) suggest that early childhood education providers' familiarity with, knowledge of, and confidence related to the implementation of health-promoting policy, system and environment change significantly increased after the professional development training (p <0.05). No significant differences in these individual-level constructs were found between centre-based and home-based providers. The HEP also resulted in significant changes in environmental-level constructs; 154 total health-promoting changes (averaging 3.5 changes/setting) were implemented in 44 early childhood education settings. Conclusion: Facilitation of a strategic planning process in a professional development training format resulted in improvements in individual- and environmental-level constructs related to healthy eating and physical activity behaviours and provides a novel way to foster sustainable health-promoting environments in early childhood education centres and homes.