The present study is an in-depth qualitative inquiry with an established theater troupe composed of adults living with psychiatric disabilities known as The Stars of Light. A grounded theory methodology is used to describe dimensions of social activism and characteristics of theater as a medium of engagement at the individual, setting/troupe, and community levels of analysis. Analysis of a broad scope of interview data, performance content, community contacts, and historical data from the troupe's 19-year history led to the identification of eight emergent theoretical concepts formulated from 17 supporting associated themes. The theoretical concepts characterize the impacts of community-based theater in the lives of participants, and theater troupe processes that contribute to community education and positive social change for adults living with psychiatric disabilities. Advantages, limitations, and future directions for research and action in community-based theater settings are discussed within the context of present research findings.