While there is a widespread view that business-nonprofit collaboration creates the opportunity to effectively address sustainability-related challenges, we still have limited understanding of the mechanisms through which these interorganizational relationships contribute to the creation of social and business value. We address this gap by adopting a profit-based organization's perspective and investigating the microfoundations of the firm’s dynamic capability for social responsibility. Drawing on a case study of a business-nonprofit collaboration, the paper examines how the micro-processes within the firm shaped that interorganizational relationship. We offer a framework that explains how key microfoundations of sensing, seizing, and transforming capabilities are developed and deployed in different stages of the collaboration. We find that this process is built upon a combination of routinized mechanisms and managerial ad-hoc interventions that shape the underlying role that cognition plays in the social issue that began with pure altruism and shifted to instrumental framing over time.