The imperative of climate change has inspired hundreds of cities across the United States to act to reduce greenhouse gas emissions. Yet in some contexts, urban greening and climate action have exacerbated social injustices, spawning green gentrification or increasing the cost of living. In response, cities are beginning to shift their governing institutions to foster collaboration between departments and build local capacities while leaning into the interconnected nature of climate change mitigation, housing affordability, and social justice. Through a cross-case comparison of Denver, Colorado and Salt Lake City, Utah, two cities committed to climate action while facing severe housing crises, this study argues that cities are entering a new phase of urban climate action, one that can build a more sustainable and equitable urban environment for all.