This brief is one in a five-part series in which the Collaborative for Academic, Social, and Emotional Learning (CASEL) documents insights from their efforts to understand how educators and researchers can build relationships that support a shared action research agenda around social and emotional learning (SEL). CASEL has developed three theories of action, guided by four focus areas that are scaled to their position within the system. Each theory of action provides a roadmap to systemic SEL implementation. This Research-Practice Partnership (RPP) series inquiry seeks to demonstrate the emerging coherence of CASEL's theories of action across the tiers of our education system and provide insights into where additional action and support are needed to foster equitable learning and development for children from diverse backgrounds. Specifically, they want to understand how actions within CASEL's State Theory of Action influence district and school actions. When states engage in the activities within the State Theory of Action, the assumption is that states are creating the conditions for districts and schools to implement systemic SEL. To begin exploring those assumptions in this RPP, CASEL and Wisconsin's Department of Public Instruction (DPI) co-constructed research questions to examine ways in which its resources, guidance, and professional learning promote systemic SEL. The insights presented here were co-constructed by CASEL with DPI staff. This RPP presents evidence supporting how a state education agency (SEA) can approach and lead SEL professional learning and the influence these sessions have on the perceptions and actions of district- and school-level educators that attended the professional learning.