The increasing professionalization of creative storytelling for social change has led to the rise of impact intermediaries whose main role it is to amplify the impact of creative stories by using them to raise awareness about social issues, change behaviors and policies. In this process, ambiguity around the greater meaning of creative stories is both an opportunity and a challenge. Based on rich data on film-based impact campaigns, we examine how intermediaries amplify the social impact of creative stories while navigating narrative ambiguity. We find that they engage in various practices allowing for openness to multiple story interpretations to reach across different impact partners and audience groups while customizing stories in pursuit of specific social change objectives. Findings have important implications for research on intermediaries, creative and entrepreneurial storytelling, and organized system change.