BackgroundTrained intensivist staffing improves survival outcomes in critically ill patients at intensive care units. However, the impact on outcomes of critically ill patients with coronavirus disease 2019 has not yet been evaluated. We aimed to investigate whether trained intensivists affect outcomes among critically ill coronavirus disease 2019 patients in South Korean intensive care units.MethodsUsing a nationwide registration database in South Korea, we included adult patients admitted to the intensive care unit from October 8, 2020, to December 31, 2021, with a main diagnosis of coronavirus disease 2019. Critically ill patients admitted to intensive care units that employed trained intensivists were included in the intensivist group, whereas all other critically ill patients were assigned to the non-intensivist group.ResultsA total of 13,103 critically ill patients were included, with 2653 (20.2%) patients in the intensivist group and 10,450 (79.8%) patients in the non-intensivist group. In the covariate-adjusted multivariable logistic regression model, the intensivist group exhibited 28% lower in-hospital mortality than that of the non-intensivist group (odds ratio: 0.72; 95% confidence interval: 0.62, 0.83;P< 0.001).ConclusionsTrained intensivist coverage was associated with lower in-hospital mortality among critically ill coronavirus disease 2019 patients who required intensive care unit admission in South Korea.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40560-023-00668-1.