The green city is recognized as one of the approaches to achieving sustainable development and enhancing urban livability, having been shaped by political, ecological, and social factors. Accordingly, this study seeks to examine the evolution of green city discourse and identify the epistemic ruptures and knowledge–power mechanisms governing urban planning. In terms of purpose, this research is fundamental, and in terms of nature, it is qualitative. The research methodology is grounded in Foucauldian genealogy combined with critical discourse analysis. Data were collected through in-depth documentary and library-based studies.

The findings indicate that the evolution of green city discourse has not been merely linear, progressive, or technical; rather, it is the outcome of seven epistemic and knowledge-based ruptures. These include: urban sanitary engineering; the garden city and biopolitics; modern urbanism and spatial discipline; sustainable development and New Urbanism; ecological biopower; algorithmic biopower; and post-COVID urbanism and transhuman subjectivity. Across these epistemic ruptures, the conception of the green city has shifted from viewing nature as an instrument of sanitary engineering and cleanliness to understanding nature as a co-creator and living partner within resilience networks.

Therefore, this study argues that the green city can be interpreted beyond an environmental or technocratic phenomenon. From a Foucauldian perspective, it can be understood as a political—or biopolitical—technology through which urban governance and management are exercised. Furthermore, the findings move beyond linear historiography and critique approaches limited to quantitative measures or green branding, demonstrating that an understanding of urban environmental crises requires an examination of the hidden layers of power and truth. Finally, the study recommends that urban managers and policymakers move beyond an exclusive focus on the quantity of green space and give particular attention to emerging processes such as environmental justice, local proximities, and citizen co-creation in urban governance.