We apply an ecosystems-as-structure lens to argue that an ecosystem consists of multiple actors with different roles that each have their own strategies and activities. Ecosystems emerge and co-evolve with these actors, which are both orchestrators and complementors. To understand the mechanisms that drive forward this co-evolution, we apply the historical method to study over several decades an ecosystem that gradually moved to a shared sustainable energy value proposition. This allows us to lay out the mechanisms behind co-evolution, which we label as identification, configuration, negotiation, specification, (re-)evaluation, and implementation. We contribute to the literature on the development of ecosystems by advancing the understanding of the role different actors’ strategies and activities play in ecosystem evolution. We also generate insights into how different actors can benefit from ecosystems with joint value propositions.