This is an explorative case study that examines how ideas and concepts relating to sustainable development are factored into new approaches to urban governance in Hangzhou. The proposition is that traditional performance assessment procedures combined with innovative surveys of the city government’s social accountability and with various forms of social participation have created a new framework for urban governance, both conceptually and as a series of practical measures. More specifically, the study examines a dramatic redesign of the performance assessment system in Hangzhou aimed at developing transparency of government and new forms of public accountability. This could pave the way for further progress with regard to development of sustainable city governance due to the strategic green turn pursued by Hangzhou’s leadership for some years now.