Theories of learning typically downplay the interplay between social structure and student agency. In this article, we adapt a causal hypothesis from realist social theory and draw on wider perspectives from critical realism to account for the development of capacity to engage in reflection on professional practice in academic roles. We thereby offer a theory of professional learning that explores how social and cultural structures and personal emergent powers combine to ensure variation in the emergence of such reflective capacity. The influence of these factors on professional learning is mediated through reflexive deliberation and social interaction, with the exercise of one's personal powers specifically identified as a stratum of social reality. We consider further the role of concerns, intention and attention in professional learning, drawing together issues that are rarely considered within the same theory. We thus offer a comprehensive account of professional learning, showing how a focus on structure and agency increases the explanatory power of learning theory. (Contains 1 figure.)