Objective <p>Ethical practice is a core professional expectation in nursing, yet nursing interns may vary substantially in how they enact ethical principles during clinical placements. This study examined ethical behavior among nursing interns through latent profile analysis and explored personal and environmental determinants.</p> Methods <p>A cross-sectional survey was conducted in October 2024 with 369 nursing interns from a tertiary hospital in Wuhan, China. Instruments included a demographic questionnaire, the Ethical Behavior Scale for Nurses, and the Nurses’ Moral Courage Scale. Latent profile analysis was used to classify nursing interns’ ethical behavior into different profiles. Univariate group-comparison tests and multinomial logistic regression were used to determine factors that were associated with different profiles.</p> Results <p>Three distinct ethical behavior profiles were identified: Moderate–Balanced (37.7%), Technical-Priority &amp; Fairness-Neglect (13.6%), and Consistent High-Scorer (48.8%). Compared with Consistent High-Scorers, males and those who had received patient complaints were more likely to belong to the Moderate–Balanced or Technical-Priority &amp; Fairness-Neglect profiles. Higher moral courage and stronger professional passion were associated with lower odds of Moderate–Balanced profile membership.</p> Conclusion <p>More than half of the interns were classified into suboptimal profiles, highlighting the need to strengthen everyday ethical practice. Educational methods need to transcend uniform approaches, emphasizing the development of moral courage and professional enthusiasm through ethics-centered simulations. Establishing supportive clinical environments with structured feedback mechanisms is essential to guide interns toward consistently high ethical performance.</p>