Dietitians learn clinical decision making (CDM) predominantly as an autonomous cognitive process that considers the needs and preferences of the patient. Although interprofessional education is increasing in tertiary dietetic programmes, a paucity of research exists that explores the nature of how practising dietitians make decisions, independent or otherwise. This qualitative interpretative study explored the nature of experienced dietitian CDM in the acute care setting. Philosophical hermeneutic principles guided text construction and interpretation via in-depth, semi-structured interviews with practising dietitians with at least 3 years of experience. A reference focus group commented on the emerging findings, increasing the rigour of the research. Ten dietitians participated in the interviews and there were five dietitians in the reference focus group. CDM was found to be a highly social phenomenon with varying degrees of autonomy involving complex power relations with various other health professionals, in particular, medical practitioners. Dietitians respond to existing power relations in key ways, including building and maintaining relationships, advocating on behalf of the patient and negotiating decisions with other healthcare staff when in pursuit of improved health and nutrition related outcomes for patients. Strategic interprofessional communication skills are foundational to effective patient care and advancing the role of the dietitian. Power and autonomy in dietitian CDM are important concepts that could inform interprofessional education when seeking to promote both effective dietetic and interprofessional practice.