Research has shown that factors such as teaching confidence and a sense of belonging influence an educator’s classroom practice and motivation to remain in the profession. While professional learning programs focused on CS content and pedagogy abound, opportunities to develop these affective components are often scarce for K-12 teachers. This is particularly true for those who are the sole CS educators at their school or are thrust into CS teaching with minimal preparation. To address this gap in support, we developed a peer mentoring program for high school teachers, featuring one-on-one mentoring focused on goals aligned with the Computer Science Teachers Association Standards for CS Teachers, a monthly community of practice for mentors to enhance their mentoring skills to better support their mentees, and numerous opportunities for community building among all participants. Drawing on four years of experience partnering with three CS teacher communities and analyzing evidence of growth from survey and interview data, we illustrate how we designed a program that fosters the professional development of both mentors and mentees, while incorporating a focus on equitable CS teaching. As more stakeholders create programs to support in-service and pre-service teachers transitioning to CS education, the insights shared in this experience report can provide guidance on developing initiatives that holistically support educators and contribute to a more sustained and well-prepared K-12 CS teaching workforce.