ABSTRACT Social workers frequent interprofessional healthcare teams, but few studies examine the day-to-day experiences of these providers on interprofessional teams. Our study utilized semi-structured interviews with 54 medical social workers practicing on interprofessional healthcare teams. A thematic analysis was used to analyze the day-to-day functions of these social workers. The analysis resulted in three primary themes: 1) Social Workers’ Self-Perceptions of their Roles within Interprofessional Teams, 2) Social Workers Shifting Roles on Interprofessional Teams, and 3) Interprofessional Team Dynamics that Impact the Role of a Social Worker. Social workers perceived their primary roles as contributing a unique systems approach to interprofessional healthcare teams while emphasizing patient self-determination. These self-perceptions influenced their shifting roles on interprofessional healthcare teams (e.g. clinician, case manager, bridge builder). In addition to individual self-perceptions, the healthcare system infrastructure influenced social work roles. For example, social workers in outpatient settings more frequently assumed the role of a mental health practitioner compared to those in inpatient settings. Last, there was variation in interprofessional communication and workflow assignment based on the healthcare infrastructure. Future research should examine the education and training efforts of social workers and other allied health professions for interprofessional healthcare teams.