In autologous stem cell therapy, cell characteristics determine the potency of stem cells for regeneration. Aging and ischemia are two factors that are often neglected in pre-clinical tests for stem cell therapy. Here, we characterized cardiac explant-derived cells (EDCs) with a focus on distinguishing the effect of age and ischemia and then we looked for the effects of the combination of the two factors. We observed that ischemia worsens the age effect on EDCs. EDCs that were derived from aged mice with a history of myocardial infarction showed the highest number of senescent cells with dysregulation of the DNA repair system resulting in activation of cell cycle checkpoints. We over-expressed the anti-senescence Mybl2 transcription factor in EDCs from ischemic aged mice. The senescent state, paracrine profile and superoxide dismutase antioxidant enzyme activity improved in these cells. In vivo, we observed a boost in the potency of the Mybl2-modified EDCs, with an increase in short-term engraftment leading to improved heart function in infarcted mice. In general, Mybl2 over-expression rejuvenates senescent EDCs.