(1) Background: The effects of exercise-based cardiac rehabilitation (CR) on left ventricular function in patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI) are important but poorly understood. (2) Purpose: To evaluate the effects of an exercise-based CR program (exercise training alone or combined with psychosocial or educational interventions) compared with usual care on left ventricular function in patients with AMI receiving PCI. (3) Data sources, study selection and data extraction: We searched PubMed, WEB OF SCIENCE, EMBASE, EBSCO, PsycINFO, LILACS and Cochrane Central Register of Controlled Trials databases (CENTRAL) up to 12th June 2021. Article selected were randomized controlled trials and published as a full-text article. Meta-analysis was conducted with the use of the software Review manager 5.4. (4) Data synthesis: Eight trials were included in the meta-analysis, of which three trials were rated as high risk of bias. A significant improvement was seen in the exercise-based CR group compared with the control group regarding left ventricular ejection fraction (LVEF) (std. mean difference = 1.33; 95% CI:0.43 to 2.23; p = 0.004), left ventricular end-diastolic dimension (LVEDD) (std. mean difference = −3.05; 95% CI: −6.00 to −0.09; p = 0.04) and left ventricular end-systolic volume (LVESV) (std. mean difference = −0.40; 95% CI: −0.80 to −0.01; p = 0.04). Although exercise-based CR had no statistical effect in decreasing left ventricular end-systolic dimension (LVESD) and left ventricular end-diastolic volume (LVEDV), it showed a favorable trend in relation to both. (5) Conclusions: Exercise-based CR has beneficial effects on LV function and remodeling in AMI patients treated by PCI.