Addressing societal issues increasingly requires multistakeholder collaboration. Yet, cross-sector partnerships (CSPs) are often difficult to form and maintain because of coordination problems and conflicting interests of the organizations involved. To better understand how organizations overcome these challenges, we take a micro-foundational approach. First, we conducted an in-depth case study of a consulting firm to examine the emergence of a platform for CSPs. Second, using survey data from 665 employees, we identified critical elements that contributed to the stability of the platform. Our findings reveal how a for-profit organization can play a key role in coordinating other organizations to achieve social impact. We found that the emergence and stability of the platform were based on a novel operating model that aligned senior leaders’ interests in improving employee retention, employees’ desire for meaning in their work, and employees’ willingness to make short-term financial sacrifices to participate. Our study suggests that for-profit firms can play a central role in social impact collaborations but that doing so requires alignment of internal interests through intrapreneurship. It also underlines the potential value of using a micro-foundation approach in future research into CSPs.