Due to the increasing mental health needs of children, schools have been tasked with supporting academic and social emotional needs of students. One component of mental health and wellness that is growing in popularity in the school environment is social emotional learning, or SEL. This qualitative multiple case study explored factors influential to the principal's SEL adoption and implementation experience during the first year of implementation in kindergarten and first grade. Further, this study explored how SEL instruction was adapted to meet the virtual learning experiences of students and staff due to COVID-19. A conceptual framework, based upon Rogers' (2003) Diffusion of Innovation Theory, guided the study. Six principals, identified as early adopters, from five regions in a Virginia school district, participated in the study. In addition to a review of school level data and SEL curriculum resources, semi-structured interviews were completed with principals. Principals in this study described factors such as vision and professional learning (knowledge) and perceived benefits, input from stakeholders, and alignment of initiatives (persuasion) as influential to their early adoption of the SEL initiative. Dedicated time, curriculum, coaching support, and virtual adaptation contributed to the principals' SEL implementation experiences. As implementation occurred during the COVID-19 pandemic, principals highlighted the morning meeting structure, virtual adaptation of the curriculum, and an increased focus on adult SEL. Implications of this study speak to developing best practices for SEL in a virtual environment, dedicated time for implementation, providing SEL support to staff and students, and engaging families in supporting SEL at home. Future research should explore the implementation experiences of students, teachers, and families, include grades beyond kindergarten and first grade, and compare implementation outcomes in physical and virtual environments. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]