The integrin CD49a marks highly cytotoxic epidermal-tissue-resident memory (TRM) cells, but their differen-tiation from circulating populations remains poorly defined. We demonstrate enrichment of RUNT family tran-scription-factor-binding motifs in human epidermal CD8+CD103+CD49a+ TRM cells, paralleled by high RUNX2 and RUNX3 protein expression. Sequencing of paired skin and blood samples revealed clonal overlap be-tween epidermal CD8+CD103+CD49a+ TRM cells and circulating memory CD8+CD45RA-CD62L+ T cells. In vitro stimulation of circulating CD8+CD45RA-CD62L+ T cells with IL-15 and TGF-b induced CD49a expres-sion and cytotoxic transcriptional profiles in a RUNX2-and RUNX3-dependent manner. We therefore identi-fied a reservoir of circulating cells with cytotoxic TRM potential. In melanoma patients, high RUNX2, but not RUNX3, transcription correlated with a cytotoxic CD8+CD103+CD49a+ TRM cell signature and improved pa-tient survival. Together, our results indicate that combined RUNX2 and RUNX3 activity promotes the differ-entiation of cytotoxic CD8+CD103+CD49a+ TRM cells, providing immunosurveillance of infected and malig-nant cells.