Purpose: While emergency department nurses in Indonesia are critical to quality care, the role lacks recognition and standard practices and regulation of scope of practice are absent. This research explored the role of nurses in Indonesian EDs. Method: The conceptual lens applied in the research was grounded theory. The main data source was 51 semi-structured interviews with 43 ED nurses, three directors of nursing, three nurse leaders and two nurse educators. Data were also generated through observations and memos. Results: Two key categories were constructed; shifting work boundaries and lack of authority. Shifting work boundaries was symbolic of a lack of professional authority and legitimized knowledge. Lack of authority reflected the dimension of professional autonomy through the nexus of power and knowledge. The interrelationship of these two concepts constructed a core category, securing legitimate power, which underpinned the positioning of nursing in Indonesia. Conclusions: The interconnection between political gains, tertiary knowledge, professional regulation and implementation of gender-sensitive policies was critical to the development of the ED role, the positioning of nursing within the health care system and improvement in quality of care.