Background: The optimal timing for percutaneous coronary intervention (PCI) in non–ST-segment elevation myocardial infarction (NSTEMI) remains controversial, particularly when intervention is delayed beyond 24 hours. The present study explores the clinical outcomes and functional recovery—focusing on left ventricular function—associated with different intervals of delayed PCI. Methods: In this prospective study, 120 NSTEMI patients who underwent PCI more than 24 hours after the index event were evaluated. Participants were grouped according to the time from symptom onset to revascularization (24–48 hours, 48–72 hours, and >72 hours). Baseline clinical data, risk profiles, and echocardiographic parameters were recorded. The primary outcomes included improvements in ejection fraction (EF) and global longitudinal strain (GLS). Mortality and major adverse cardiac events (MACE) were tracked for up to 6 weeks post-PCI. Results: Out of 120 patients, 56.67% underwent PCI between 24 and 48 hours, 25% between 48 and 72 hours, and the remaining beyond 72 hours. Patients revascularized at 24–48 hours demonstrated the greatest improvement in EF (88.24%) and GLS (94.12%). In contrast, those treated beyond 72 hours exhibited significantly lower, yet still notable, improvements. The rate of in-hospital complications was low across all groups, with an overall mortality of 4.17%. Risk factors such as diabetes, hypertension, and smoking status did not differentially affect the benefit of earlier versus later PCI in this cohort. Conclusion: Delaying PCI beyond 24 hours does not preclude significant clinical and functional improvement in NSTEMI patients. An intervention window of 24–48 hours appears optimal for maximizing LV functional recovery, although salvageable myocardium and clinical stability may allow benefits even after 72 hours. Further prospective trials are needed to definitively recommend the best timing strategy for these patients.