Background: Ischemic stroke is one of the serious neurological complications of coronavirus disease 2019 (COVID-19). However, ischemic stroke can develop secondary complications after cardiac involvement in COVID-19. Case Report: We report the case of a 22-year-old patient who presented with malignant cerebral infarction 10 months after COVID-19-related myocarditis. A 22-year-old woman was referred to the emergency room because of abnormal mental status changes. She developed heart failure and arrhythmia after COVID-19-related myocarditis. Brain magnetic resonance imaging (MRI) revealed high signal intensity on diffusion-weighted imaging that was indicative of acute cerebral infarction in the left middle cerebral artery (MCA) and left anterior cerebral artery (ACA) territory. In addition, occlusion of both the left MCA and ACA was observed on brain MRI. Craniectomy with therapeutic hypothermia was performed to treat the cerebral edema. Conclusion: This case suggests that caution is needed in survivors with secondary complications after COVID-19.