High-quality learning environments are critical to support students’ learning and development. This study supported eight lead teachers of Starting Strong classrooms in four different early learning programs to try to improve teachers’ knowledge, self-efficacy, and use of Developmentally Appropriate Practices (DAP) within their classrooms. Four Starting Strong supports were evaluated during this research, including an asynchronous video series, coaching with use of the Continuous Quality Improvement (CQI) Report, and Community of Practice (CoP) meetings. The Early Childhood Environment Rating Scales, Third Edition (ECERS-3) was used to measure the overall quality of preschool classrooms before and after the intervention. Pre- and post-intervention surveys were also conducted to measure participants' knowledge and self-efficacy. While there was no change in participant knowledge of DAP or self-efficacy, there was significant improvement in the ECERS-3 scores from the Spring to the Fall assessment. All participants reported the four Starting Strong supports as being very useful and offered suggestions for improvements, explicitly suggesting consistency and shared learning experiences. Collectively, the Starting Strong supports helped the teachers apply their knowledge of developmentally appropriate practices in early childhood education in establishing quality preschool environments.