Background <p>As mental health professionals, psychiatric nurses have the knowledge and skills to play a key role in responding to the psychological needs of physically ill patients. However, their presence in non-psychiatric wards is often accompanied by role ambiguity and limited use of specialized competencies. The aim of this study is to explain the experiences of psychiatric nurses concerning the role of their specialized competencies on their work experiences in non-psychiatric wards.</p> Method <p>This qualitative study employed a conventional content analysis approach. Data were collected between February and December 2024 through unstructured interviews with 16 psychiatric nurses working in non-psychiatric wards of different hospitals in Iran. Data analysis was conducted concurrently with data collection using the qualitative content analysis method described by Graneheim and Lundman (2004).</p> Results <p>Three main categories and ten subcategories were identified: (1) “Usefulness of mental health nursing skills in physical care alongside the perceived need for improvement” with subcategories “clinical application of mental health nursing skills”, “early identification and anticipation of psychological outcomes”, and “perceived need for empowerment in applying mental health nursing skills”; (2) “Enhancement of interpersonal and interprofessional interactions” with subcategories “improved interaction with the treatment team”, “establishing more effective communication with patients”, “attention to nonverbal skills and empathy in communication”, and “re-recognition of the importance of psychiatric nurses’ roles”; and (3) “Expansion and deepening of the professional role” with subcategories “generalization of mental health nursing skills to personal life and individual growth”, “performing informal advisory and supportive roles in the ward”, and “achieving a holistic approach to care”.</p> Conclusions <p>Psychiatric nurses in non-psychiatric wards utilize their specialized competencies by integrating mental health care into physical care, enhancing therapeutic and interprofessional communication, and developing their professional roles. These findings also highlight the need for further development of practical competencies in non-psychiatric settings.</p> Trial registration <p>Not applicable.</p>