This embedded case study of the Chicago School of Civics and Philanthropy (CSCP) illustrates the development of disciplinary boundaries during a transitional period of professionalization in the social sciences, particularly for the fields of sociology and social work. Drawing on archival data (e.g., reports, scholarly and autobiographical writings, and correspondence) we first document sociological contributions of the community-based school, one of many progressive projects among social settlements and social gospelers of the day. Then using the lens of an intergenerational struggle reflective of the historical social movements of the period, we analyze the circumstances surrounding the 1920 merger of the CSCP with the University of Chicago. Succeeding their early social settlement mentors, Graham Taylor of the Chicago Commons and Jane Addams and Julia Lathrop of Hull House, a second generation of social reformer proteges became a formidable force in this disciplinary differentiation. This case can be read as a micro-level illustration of a much larger macro-level political contest as professional social scientists vied for control of the definition of social science and its applied mission. The "ghosts of sociologies past" still haunt the discipline today offering important lessons for sustaining a science that joins theory with action to solve social problems.