Purpose of Review <p>This review synthesizes contemporary evidence (2020–2025) on long-term β-blocker therapy after myocardial infarction (MI) in patients with preserved or mildly reduced left ventricular ejection fraction (LVEF ≥ 40%), with a focus on incremental benefit in the modern reperfusion era.</p> Recent Findings <p>Recent randomized trials conducted in predominantly revascularized populations receiving contemporary secondary prevention therapy demonstrate neutral effects of long-term β-blocker use on all-cause mortality, recurrent MI, and heart-failure hospitalization in patients without reduced ejection fraction. The REDUCE-AMI trial showed no benefit in patients with strictly preserved LVEF (≥ 50%), and REBOOT demonstrated similar neutral outcomes in patients with LVEF &gt; 40%. A 2025 individual-patient data meta-analysis pooling five contemporary randomized trials (17,801 patients) confirmed the absence of prognostic benefit from β-blocker therapy in preserved EF. In contrast, a separate 2025 individual-patient–data meta-analysis demonstrated a significant reduction in death, recurrent MI, or heart-failure hospitalization among patients with mildly reduced EF (40–49%).</p> Summary <p>Contemporary evidence supports an ejection fraction stratified approach to β-blocker therapy after MI: routine long-term β-blocker use provides no prognostic benefit in patients with preserved EF, whereas patients with mildly reduced EF appear to derive meaningful clinical benefit. These findings support individualized, risk-based treatment strategies and underscore the need for future EF-specific randomized trials.</p>