A prospective cohort study of 200 patients with acute ischemic stroke (AIS) evaluated early neurological improvement (ENI) within 24 hours as a predictor of 90-day functional outcome. ENI was defined as the change in NIHSS score (ΔNIHSS = NIHSS at baseline – NIHSS at 24 hours). Out of 200 patients, 118 (59.0%) achieved a good result (mRS 0–2). Model 1 with age, baseline NIHSS, ASPECTS, and hypertension had an AUC of 0.863. Adding ΔNIHSS to Model 2 preserved discrimination (AUC 0.855) but reduced prediction error by 47% (from 0.051 to 0.027). Greater ENI was independently associated with good outcome (adjusted OR 1.48 per 5-point increase in ΔNIHSS; 95% CI 1.11–1.97). The study recommends incorporating ENI into prognostic assessment for better individualized care.