This paper evaluates the role of epistemic communities in shaping local environmental policy, through the case of management of environmental change through planning and greenspace in Fukuoka City, Japan. Amidst increasing global interest in the role of evidence-based policy and urban science in responding to environmental issues in cities, Fukuoka is distinctive. Locally-situated scholars in Fukuoka have, for several decades, sought to shape local responses to environmental change by influencing policy for the built environment and greenspace. Through analysis of scholarly outputs produced by scholars working at universities and research institutes within Fukuoka and policy documentation produced by the city government, we characterise the development of Fukuoka's urban environmental change epistemic community. We suggest that built environment and greenspace policy to respond to environmental change in Fukuoka has been shaped by an epistemic community in three ways. These are: (a) a common belief in techno-scientific evidence derived from empirical observation; (b) a shared interest in urban planning and greenspace as a vehicle for realising change; and (c) a common normative concern with citizen wellbeing, rooted in negative historical experiences with pollution. We argue that policy formation driven by scholarly expertise in cities may have a greater chance of taking root if there is a favourable historical context of locally-led environmental science research, personal investment of the epistemic community members in the city, and regular dialogue between the epistemic community and wider society in the city. We conclude that a strong and reflexive epistemic community, working in collaboration with environmental and civil society actors, is important in understanding an appropriate response to current urban environmental challenges.