Institutional entrepreneurship research has described and conceptualized dramatic cases of successful institutional change. We know less about whether it can help people trying to change institutions, for example, struggling to change the energy system. Do concepts from the institutional entrepreneurship literature offer sustainable energy practitioners insights on the political aspects of their work? And vice-versa: do practitioners have useful insights on the potential and limits of agency in institutional change? The present study contributes to these questions through collaborative inquiry together with government-affiliated organizations with a mission to promote sustainable energy. The results suggest that concepts from the institutional entrepreneurship literature do serve to make practitioners’ implicit competencies explicit and hence a legitimate subject for organizational development and joint learning about the political aspects of energy systems change. We conclude that institutional entrepreneurship appears to require a form of organizing that combines environmental scanning, grand strategy and everyday tactical moves on the ground.