We selected critically ill patients with coronavirus disease 2019 (COVID-19) who were receiving extracorporeal membrane oxygenation (ECMO) support and had been transferred to experienced centers. Thus, we aimed to evaluate factors that were associated with receiving ECMO support and factors that were associated with patient mortality. Using data from the National Health Insurance Service and Korea Disease Control and Prevention Agency in South Korea, adult patients admitted to an intensive care unit from October 8, 2020, to December 31, 2021, with a main diagnosis of COVID-19 were included. They were divided into two groups: ECMO group (n = 455) and non-ECMO group (n = 12,648). Receiving ECMO support was less associated with old age [odds ratio (OR), 0.95; 95% confidence interval (CI), 0.94–0.96; p < 0.001], underlying severe disabilities (OR, 0.49; 95% CI, 0.29–0.83; p = 0.008), and booster vaccination status (second: OR, 0.61; 95% CI, 0.39–0.94; p = 0.024; third: OR, 0.40; 95% CI, 0.25–0.65; p < 0.001). In addition, after adjusting for various variables, low mortality in patients with ECMO support was associated with having previously received a second booster vaccination (OR, 0.33; 95% CI, 0.14–0.77; p = 0.010). Vaccination and booster therapy may lower the need for ECMO support and lower mortality among critically ill patients with COVID-19 with ECMO support.