Myocardial infarction remains a leading cause of heart failure because current reperfusion therapies cannot prevent adverse ventricular remodeling or restore lost cardiomyocytes. Regenerative strategies based on stem cells and extracellular vesicles (EVs) have emerged as promising approaches; however, their clinical efficacy is limited by poor retention, rapid clearance, and the hostile post-infarction microenvironment. This narrative review critically examines the role of biomaterial-assisted delivery systems in enhancing stem cell and EV-based cardiac regeneration, with particular emphasis on the distinction between biomimetic and bioactive biomaterials, mechanisms of action, preclinical and clinical evidence, translational barriers, and emerging regenerative technologies. Current evidence demonstrates that injectable hydrogels, extracellular matrix-derived scaffolds, cardiac patches, conductive biomaterials, and multifunctional delivery platforms improve therapeutic retention, prolong paracrine signaling, and actively modulate inflammation, angiogenesis, fibrosis, and extracellular matrix remodeling, resulting in superior functional recovery compared with conventional delivery approaches in preclinical models. Nevertheless, robust clinical evidence remains limited because few biomaterial-assisted strategies have advanced beyond early-phase studies. Future progress will depend on integrating smart biomaterials with engineered extracellular vesicles, gene editing, and personalized regenerative approaches, together with standardized manufacturing, harmonized regulatory frameworks, and adequately powered clinical trials.