Community-Based Learning (CBL) within science, technology, engineering, and mathematics (STEM) has the potential for positive student learning outcomes while also promoting beneficial outcomes in partner communities, yet complexity of practice can often obscure or limit these outcomes. Emergent behavior makes realizing outcomes, especially those for the community, difficult. A systems-level approach can minimize some complexity, yet empirical evidence of how STEM CBL is structured is limited. A three-tiered model (i.e., Community, Program, and Individual levels) is used as a structural framework to analyze two case studies to answer: How do three system levels describe the STEM CBL practitioners, their actions, and goals? Thematic analysis of data generated through participant-observation within two purposefully selected cases establishes a foundation for how these system levels can impact practice. Distribution of effort across the three levels can support well-rounded CBL practice and advance the voices of all practitioners, but especially those with less power.