Professionalization has become ubiquitous among a broad range of organizations, promising increased efficiency and legitimacy. However, extant research depicts professionalization mostly as a binary change and largely ignores its temporal and processual nature, resulting in a lack of insights into how professionalization unfolds and how organizations deal with its inherent tensions. Therefore, we take a processual perspective on professionalization, studying it as a transformation toward a more rationalized, managerialized, and formalized organization through multiple practice adoption. Relying on a longitudinal single case study of a Swedish family firm that professionalized its business and family ownership domains, our processual analysis reveals unique types of professionalization and four practice interaction mechanisms through which organizations deal with tensions in the professionalization process. We contribute by conceptualizing a process model of professionalization, casting light on practice interaction mechanisms, and outlining implications of professionalization for organizational goals.