Background and purpose: Despite successful recanalization following endovascular mechanical thrombectomy (EVT) in patients with large-vessel occlusive stroke, a subset of patients continues to experience poor outcomes. This study aims to analyze the association between core infarct growth rate and patient prognosis, and to examine the interaction between infarct growth rate (IGR) and hypoperfusion intensity ratio (HIR). Methods: We retrospectively analyzed 142 patients with acute anterior circulation occlusion who achieved successful recanalization following EVT, defined as modified Thrombolysis in Cerebral Infarction (mTICI) grade 2b or 3. Patients were stratified into good (modified Rankin Scale [mRS] 0–2) and poor (mRS 3–6) prognosis groups based on 3-month mRS scores. IGR was calculated as the infarct core volume divided by the time from symptom onset to imaging. Infarct core volume was delineated as the volume of brain tissue with relative cerebral blood flow 10 s to that with T _max > 6 s on CT perfusion imaging. Multivariate logistic regression was used to identify independent predictors of clinical outcome, and receiver operating characteristic curves were generated to evaluate their prognostic value. Results: Among the 142 patients, 91 achieved a good outcome (mRS 0–2), whereas 51 had a poor outcome (mRS 3–6). The cohort included 103 males (72.5%), with a median age of 68 (IQR: 58–74) and a median baseline NIHSS of 13 (IQR: 9–15). Multivariate analysis identified hypertension (odds ratio [OR] = 5.14, 95% CI: 1.15–22.87), baseline NIHSS score (OR = 1.25, 95% CI: 1.07–1.46), IGR (OR = 1.10, 95% CI: 1.01–1.21), HIR (OR = 380.71, 95% CI: 6.29–23,037.59), and cystatin C levels (OR = 26.65, 95% CI: 2.19–324.55) as independent predictors of poor outcome. HIR was the primary determinant of IGR, with higher HIR significantly associated with accelerated infarct growth (adjusted OR = 18.75, 95% CI: 2.45–143.54; p = 0.005). Conclusion: Hypertension, baseline NIHSS score, IGR, HIR, and cystatin C levels are independent predictors of poor functional outcome despite successful recanalization. Among these, HIR demonstrated strong discriminatory power in identifying patients with rapid versus slow infarct progression.