There is a growing understanding that design can positively contribute towards highly complex social, economic and environmental problems we face today. One key area is citizen empowerment to change built-in systemic inequalities and exploitative practices. This paper presents a design intervention that explored citizen empowerment in the context of The Fair Energy Mark campaign, a citizen-led action aimed to raise practice standards and address power imbalances in the energy supply sector. The project-based investigation explored the tensions emerging between expert–diffuse design in the process of elaboration of campaign branding and communication strategy. The researchers experimented with new tools that enabled an open participatory process of campaign framing, but also facilitated fluid knowledge exchange between participants through experiential learning. The investigation contributes some conceptual constructs to discuss strategic design management practice in the socio-political sphere. Furthermore, the research identified that a closer integration of design and communicative action theories, and participatory design and community organising methodologies present promising opportunities to amplify the impact of design research for social change.