Urban sustainability approaches focusing on a wide range of topics such as infrastructure and mobility, green construction and neighbourhood planning, or urban nature and green amenities have attracted scholarly interest for over three decades. Recent debates on the role of cities in climate change mitigation have triggered new attempts to conceptually and methodologically grasp the cross-sectorial and cross-level interplay of enrolled actors. Within these debates, urban and economic geographers have increasingly adopted co-evolutionary approaches such as the social studies of technology (SST or ‘transition studies’). Their plea for more spatial sensitivity of the transition approach has led to promising proposals to adapt geographic perspectives to case studies on urban sustainability. This paper advocates engagement with recent work in urban studies, specifically policy mobility, to explore conceptual and methodological synergies. It emphasises four strengths of an integrated approach: (1) a broadened understanding of innovations that emphasises not only processes of knowledge generation but also of knowledge transfer through (2) processes of learning, adaptation and mutation, (3) a relational understanding of the origin and dissemination of innovations focused on the complex nature of cities and (4) the importance of individual actors as agents of change and analytical scale that highlights social processes of innovation. The notion of urban assemblages further allows the operationalisation of both the relational embeddedness of local policies as well as their cross-sectoral actor constellations.