Organizational change is crucial for family firms to survive and prosper in today’s complex business environment. However, organizational change is often impeded by the difficult trade-off between change and continuity. By providing insights into new ways of working during innovation collaborations, start-ups can help introduce change in family firms. Despite increasing scholarly attention, previous research has failed to explain the role of start-ups in organizational change in family firms and their interaction with internal actors. Based on data from six cases of family firms collaborating with start-ups (including 40 qualitative interviews), we distill the mechanisms that start-ups developed to interact with internal change agents and owning families to uncover opportunities for change, initiate new practices, and facilitate their implementation and dissemination within the family firm.