STEM learning communities facilitate student academic success and persistence in science disciplines. This prompted us to explore the underlying factors that make learning communities successful. In this paper, we report findings from an illustrative case study of a 2-year STEM-based learning community designed to identify and describe these factors. A directed content analysis of 119 student narrative documents resulted in 6 content codes organized into two primary categories: "academic self-regulation," "STEM identity," "metacognition," and "self-efficacy" comprise the psychosocial or "affect" learning factors that students identified as improved as a result of their participation in the learning community; and "interaction with faculty/staff/STEM professionals," and "interaction with peers" represent the aspects of the learning community that students identified as meaningful learning community experiences related to their academic development. In addition, we analyzed 3 sets of code co-occurrences to understand how the content codes interrelate. Our findings indicate that certain psychosocial learning factors are developed through social interactions within the context of learning community participation, which may help explain the positive effects of student participation in learning communities.