The effect of serum glucose-to-potassium ratio (GPR) on cerebrovascular diseases has been previously validated. However, the value of the GPR in patients with severe intracerebral hemorrhage (ICH) requiring ICU admission remains unclear. This study aimed to investigate the association between the GPR and the clinical prognosis of critically ill patients with ICH. This study identified patients with severe ICH requiring ICU admission from the Medical Information Mart for Intensive Care (MIMIC-IV) database and divided them into quartiles based on GPR levels. Outcomes included 30-day, 90-day, and 1-year mortality rates. The association between the GPR and clinical outcomes in critically ill patients with ICH was elucidated using Cox proportional hazards regression analysis and restricted cubic splines. In total, 2018 patients (53.8% male), with a median age of 70 years, were enrolled in the study. The 30-day, 90-day, and 1-year mortality rates were 23.9%, 30.1%, and 38.4%, respectively. Per multivariate Cox proportional hazards analysis, an elevated GPR was significantly associated with all-cause mortality. After adjusting for age, sex, Charlson Comorbidity Index, white blood cell count, red blood cell count, platelet count, and Glasgow Coma Scale, patients with an elevated GPR had a higher 30-day mortality (hazard ratio [HR]: 1.32; 95% confidence interval [CI]: 1.22–1.42; P < 0.001), 90-day mortality (HR: 1.27; 95% CI: 1.18–1.37; P < 0.001) and 1-year mortality (HR: 1.22; 95% CI: 1.14–1.31; P < 0.001) when analyzed as a continuous variable. Furthermore, analysis using restricted cubic splines demonstrated a consistent and progressive escalation in the risk of all-cause mortality with an elevated GPR. The GPR was significantly associated with short- and long-term all-cause mortality in critically ill patients with ICH. This finding demonstrates that GPR may be useful in identifying patients with ICH at a high risk of all-cause mortality.