We engineered a microneedle patch integrated with cardiac stromal cells (MN-CSCs) for therapeutic heart regeneration after acute myocardial infarction (MI). To perform cell-based heart regeneration, cells are currently delivered to the heart via direct muscle injection, intravascular infusion, or transplantation of epicardial patches. The first two approaches suffer from poor cell retention, while epicardial patches integrate slowly with host myocardium. Here, we used polymeric MNs to create "channels" between host myocardium and therapeutic CSCs. These channels allow regenerative factors secreted by CSCs to be released into the injured myocardium to promote heart repair. In the rat MI model study, the application of the MN-CSC patch effectively augmented cardiac functions and enhanced angiomyogenesis. In the porcine MI model study, MN-CSC patch application was nontoxic and resulted in cardiac function protection. The MN system represents an innovative approach delivering therapeutic cells for heart regeneration.