Nurses face many ethical challenges, placing them at risk for moral distress and burnout and challenging their ability to provide safe, high-quality patient care. Little is known about the sustainability of interventions to address this problem. To determine the long-term impact on acute care nurses of a 6-session experiential educational program called the Mindful Ethical Practice and Resilience Academy (MEPRA). MEPRA includes facilitated discussion, role play, guided mindfulness and reflective practices, case studies, and high-fidelity simulation training to improve nurses' skills in mindfulness, resilience, and competence in confronting ethical challenges. A prospective, longitudinal study was conducted on the impact of the MEPRA curriculum at 2 hospitals in a large academic medical system. The study involved surveys of 245 nurses at baseline, immediately after the intervention, and 3 and 6 months after the intervention. The results of the intervention were generally sustained for months afterward. The most robust improvements were in ethical confidence, moral competence, resilience, work engagement, mindfulness, emotional exhaustion, depression, and anger. Some outcomes were not improved immediately after the intervention but were significantly improved at 3 months, including anxiety and empathy. Depersonalization and turnover intentions were initially reduced, but these improvements were not sustained at 6 months. Many MEPRA results were sustained at 3 and 6 months after conclusion of the initial foundational program. Some outcomes such as depersonalization and turnover intentions may benefit from boosters of the intervention or efforts to supplement the training by making organizational changes to the work environment.