Just transitions, and justice in the governance of climate transition more generally, have over the last decade developed as an influential policy concept and governance concern. Just transitions have acted as a projection space for visions of a profoundly different society, but have also been used to undercut climate policies and social change altogether. At the same time, the just transition has shifted shape repeatedly and appears in the process of being superseded by other policy priorities. This Special Issue explores the emergent, dynamic career of the just transition as a multifaceted policy project. It brings together seven studies, largely rooted in European contexts, that show how justice in transition governance is being ‘done’—constructed in multiple settings, built on, dismantled and reconstructed. In this editorial, we use the metaphor of assemblage to bring the different contributions to the Special Issue together and embed them in the wider just transitions literature. We outline how diverse actors are involved in assembling the just transition and how they are, simultaneously, constructed as part of the just transition: Whilst some actors are cast as central, others are pushed to the margins. We also highlight how we, as researchers, contribute to this process of assembling and how the interaction between academic rationalities and our own normative aspirations might lead to conceptual developments that, perhaps ironically, render the just transition an impossible political project. The editorial concludes with a call for reflexivity in our critical engagement with just transitions and other, similar policy projects. © 2026 John Wiley & Sons, Ltd. and ERP Environment.