In this article we explain the relatively successful performance of the EU in climate and energy governance by essentially two factors: (1) multi-level reinforcement and (2) the mobilization of economic interests at different levels of governance through low-carbon industrial policy. The article adds to the literature by further developing existing arguments on multi-level reinforcement in climate and energy policy and discussing the role of sub- national actors in this context. Multi-level governance is most advanced in the EU compared to other world regions and is actively harnessed for climate policy and the promotion of low-carbon development objectives by the European Commission. It represents a multi- impulse system, which fosters interactive learning from best practice and provides an opportunity structure for innovation and rapid diffusion. Moreover, the authors stress the point that economic co-benefits of climate protection have been successfully mobilized at all levels of governance, including the sub-national level, in recent times. As a result, sub-national levels of governance are beginning to assume an increasingly important role in reinforcing climate and energy governance, initially promoted at the national and EU level. This is illustrated by examples from both pioneer countries and laggards in terms of national climate and energy policy.