In Rhetoric/Composition studies, agency has been a highly contested concept, straightaway invoking the tension between two dominant perspectives. Agency is viewed as either an internal quality possessed by an individual or a construction of external discourses. While such discussions seeking to define agency are important, they tend to focus on interpretation and analysis over the production of agency, which is a key component of social action. People must believe their deliberate actions can cause positive socio-political change. With this dissertation, I propose that thinking of agency as a form of rhetorical invention puts the focus on the production of agency for effective social action. In working towards this goal, I develop the notion of activist inquiry: a non-prescriptive, inquiry-oriented approach to inventing agency for social action based on Jane Addams’s rhetorical strategies in Democracy and Social Ethics.