Patient-centred care and the empowerment of patients through shared clinical decision-making is a key goal of healthcare systems internationally. The Emergency Department is one of the first opportunities for shared decision-making to occur, with information exchanged between patient and clinician, between clinical disciplines, across the continuum of care, and between clinicians and ancillary departments including radiology and pathology laboratories. The successful development and implementation of sustainable health information technology (HIT) to support shared decision-making in Emergency care requires an understanding of the factors affecting this context. From a purposive, maximum variation sample of clinicians and a convenience sample of patients across three metropolitan and regional Emergency Departments in Australia, we identified three divergent discourses from an in-depth qualitative exploration of issues around shared decision-making. This allowed us to identify unanticipated factors affecting patient-centred care to inform context-sensitive implementation of HIT in the Emergency Department.