Fernández is a professor of architecture at the Massachusetts Institute of Technology. He is director of the Urban Metabolism Group which explores the environmental and ecological consequences of cities and their economies. He is also director of the MIT Environmental Solutions Initiative, a major institute-wide effort to connect the very best research and scholarship for sustainable solutions for people, prosperity and the planet. The ESI supports a broad portfolio of work including natural climate solutions, environmental justice and energy transitions, conservation and biodiversity loss reduction and more. He has been the co-Director of the MIT International Design Center, Head of the Building Technology Program and is a practicing architect designing low and zero carbon buildings and cities.