Background Mental health nurses advocate for patients through a person-centered approach because they care for people experiencing mental distress who tend to be limited to exercising their human rights and autonomy through interpersonal relationships. Therefore, it is necessary to provide high-quality person-centered care for these patients by identifying the influencing factors. Aim This study aims to identify the factors affecting mental health nurses in performing person-centered care for patients. Research design This study had a cross-sectional, descriptive-correlational survey design. Participants and method Nurses ( N = 166) working at psychiatric wards in Korea completed an online questionnaire on moral sensitivity, attitudes toward people with mental illness, and person-centered care. The t-test and stepwise multiple regression analysis were used. Ethical considerations Ethical approval for the study was obtained from the relevant ethics committee. Findings Moral sensitivity was a significant factor correlating with the provision and perception of person-centered care. Attitudes toward patients had no effect on person-centered care. The predictor variables for the provision of person-centered care (R2 = 0.247) were moral sensitivity (β = 0.33), having a professional qualification (β = 0.19), marital status (β = 0.18), and closed ward (β = −0.15). The predictor variables for the perception of person-centered (R2 = 0.150) care were closed ward (β = −0.25), moral sensitivity (β = 0.23), and marital status (β = 0.18). Discussion and conclusion Mental health nurses can strengthen person-centered care by improving moral sensitivity related to the ethical aspect of nursing and professional competence to address the complex needs of patients. Person-centered care needs to be applied more carefully in closed wards where human rights issues may arise. Through these efforts, the dignity of patients can be protected.