Stefan is Associate Professor of Architecture and Urbanism at Carnegie Mellon University, where he chairs the Master of Urban Design program. He directs the Remaking Cities Institute, the School of Architecture's research center for urbanism, participatory action, and community design. From 2010 to 2016, he served as a Professor for Geography, Landscapes, and Cities at the Academy of Fine Arts Vienna.

Since 2006 Stefan has been working at the intersection of architecture, urbanism, and research through his design practice STUDIOGRUBER. His work focuses on spatial justice with a specific interest in the negotiation between top-down planning and bottom-up transformation of cities. His recent projects explore commoning practices, aiming to foster community ownership and resilience beyond market or state paradigms, contributing to a more equitable, resilient, and self-determined future.

Stefan has curated numerous exhibitions, including "An Atlas of Commoning" for ifa, Institut für Auslandsbeziehungen, in collaboration with ARCH+ Journal for Architecture and Urbanism, and “A Dialogue Must Take Place, Precisely Because We Don't Speak the Same Language” for the 2020 Tbilisi Architecture Biennale. He initiated "Spaces of Commoning," an interdisciplinary research project on commoning, artistic practices, and the city.

At THE NEW INSTITUTE, Stefan was involved in the program Reclaiming Common Wealth.