Sustainable urban transformation has become a mantra for Chinese cities. While most studies focus on sustainable urbanization in megacities, the far larger number of medium-sized cities is understudied, although the latter face more severe urban problems. This article develops a framework for examining policy change in sustainable urban development initiated at the central level and reactions, tensions, and implementation issues emerging at the local level. It focuses on an in-depth case study of the challenges in realizing a transition from quantity-oriented pro-growth policies to sustainable quality-oriented ones in a medium-sized Chinese city. We find that there is evidence of changes in long-term values and goals toward sustainability at the levels of both central and local government, but also great inconsistency between goals on paper and policy implementation in practice. Sustainability in urban development is much harder to realize as local officials see urban development as a major means to maintain local economic growth, which can be separated from other issues in ecological preservation. The article concludes with a roadmap for future studies focusing on medium-sized cities, especially indicating how narratives on sustainable urban development hide from view financial and environmental risks generated by the actual implementation of the dominant aggressive urban pro-growth model.