Matthias Klatt is Professor of Jurisprudence and Director of the Graz Jurisprudence Research Centre at the University of Graz, Austria. He completed his doctorate summa cum laude under Robert Alexy at the University of Kiel — the dissertation received the European Award for Legal Theory and the IVR Young Scholar Prize — and his habilitation at the University of Hamburg. He was a Junior Research Fellow at New College, Oxford, and a Law Clerk at the German Federal Constitutional Court with Justice Gertrude Lübbe-Wolff.

His central theoretical contribution is a triadic concept of law — comprising its real, ideal, and discursive dimensions — which extends and reconstructs Alexy’s dual-nature thesis into a systematic non-positivist jurisprudence. His research lies at the intersection of legal philosophy, constitutional theory, and human rights, with particular focus on the concept of law, legal argumentation, proportionality, and constitutionalism beyond the state. He is the author or editor of publications in seven languages, including The Constitutional Structure of Proportionality (Oxford University Press, 2012) and Institutionalized Reason: The Jurisprudence of Robert Alexy (Oxford University Press, 2012). He is co-editor of the Hart Studies in Constitutional Theory series (with Maartje De Visser and Charles Barzun).

He lectures frequently by invitation at universities across Europe and Latin America, with talks delivered in more than 20 countries. He is a Regular Visiting Professor at the Tarello Institute for Legal Philosophy (Genova) and at the LLM in Legal Theory (Frankfurt).