Cardiovascular disease is a leading cause of worldwide mortality. Despite the success of current therapies for acute myocardial infarction (MI), many patients still suffer irreversible damage, and the prevalence of heart failure is growing. After MI, the extracellular matrix (ECM) of the damaged myocardium is modified to produce scar tissue. This remodeling reduces the efficacy of therapies and also hinders endogenous repair mechanisms. Therefore, a strategy to prevent adverse remodeling and provide a suitable ECM environment that supports cells, tissue repair and functional restoration may lead to a superior therapeutic outcome in MI patients. Bioengineered materials are an attractive approach for achieving this. Herein, we review current research on materials that can act as a biomimetic matrix for supporting cellular repair in the post-MI heart. We also examine how nanomaterials are being used to treat the damaged heart. Finally, we provide an overview of the breakthroughs and limitations of biomaterial therapies for cardiac repair.