Scholars studying the global governance of education have noted the increasingly important role corporations play in educational policy making. I contribute to this scholarship by examining the Assessment and Teaching of twenty-first century skills (ATC21S™) project, a knowledge production apparatus operating under cognitive capitalism. I analyze how ATC21S gains symbolic power and authority as it defines what counts in education through three key processes: (1) By legitimizing and disseminating new knowledge about twenty-first century skills; (2) By implementing this knowledge concretely in schools; and (3) By embedding this new knowledge within a global alliance. I suggest that the knowledge produced by ATC21S in calculating and measuring twenty-first century skills contributes to the capture of living labor and its reproduction for the knowledge economy through the school system.