Holzner is the Executive Director of the Vienna Institute for International Economic Studies (wiiw). He is also coordinating economic policy development and communication with a focus on European economic policy. In recent years he worked on issues of infrastructure investment in greater Europe, proposing a European Silk Road.

He obtained his PhD in Economics at the Vienna University of Economics and Business in 2005. He is also a historian at the Doctoral School of Historical and Cultural Studies at the University of Vienna. Mario Holzner was a 2023 DG GROW Fellow.