During the COVID-19 pandemic, ICU professionals have faced moral problems that may cause moral injury. This study explored whether, how, and when moral injury among ICU professionals developed in the course of the COVID-19 pandemic. This is a prospective qualitative serial interview study. Two hospitals among which one university medical center and one teaching hospital in the Netherlands. Twenty-six ICU professionals who worked during the COVID-19 pandemic. None. In-depth interviews with follow-up after 6 and 12 months. In total, 62 interviews were conducted. ICU professionals narrated about anticipatory worry about life and death decisions, lack of knowledge and prognostic uncertainty about COVID-19, powerlessness and failure, abandonment or betrayal by society, politics, or the healthcare organization, numbness toward patients and families, and disorientation and self-alienation. Centrally, ICU professionals describe longitudinal processes by which they gradually numbed themselves emotionally from patients and families as well as potentially impactful events in their work. For some ICU professionals, organizational, societal, and political responses to the pandemic contributed to numbness, loss of motivation, and self-alienation. ICU professionals exhibit symptoms of moral injury such as feelings of betrayal, detachment, self-alienation, and disorientation. Healthcare organizations and ICU professionals themselves should be cognizant that these feelings may indicate that professionals might have developed moral injury or that it may yet develop in the future. Awareness should be raised about moral injury and should be followed up by asking morally injured professionals what they need, so as to not risk offering unwanted help.