Gretta Fenner is a political scientist by training and holds a masters degree from the Otto-Suhr-Institute for political science (Otto-Suhr-Institut für Politikwissenschaften) of the Freie Universität Berlin, Germany, and a degree in political sciences from the Paris Institute for Political Science (Institut d'Etudes Politiques - IEP, or "Sciences Po"). Her main fields of academic specialisation include aid effectiveness, development and corruption, and international security policy, with a geographical focus on Sub-Saharan Africa.

Before joining the Basel Institute on Governance as its Director in November 2005, she has worked at the Anti-Corruption Division of the Organisation for Economic Co-operation and Development (OECD), where she was responsible for cooperation with non-OECD member countries from Asia and the Pacific. In cooperation with the Asian Development Bank, she in particular developed and accompanied the implementation of the ADB/OECD Anti-Corruption Initiative for Asia-Pacific. In this framework, she assisted countries from the region in designing and implementing legal and institutional anti-corruption and governance reform. She further oversaw capacity building programmes in such diverse areas as prosecution of corruption, prevention of corruption in public procurement, and implementation of the UN Convention against Corruption, and directed and contributed to various publications on anti-corruption reform and institutions in the Asia-Pacific region. Also at the OECD Anti-Corruption Division, she has also been involved in similar projects in Central and Eastern Europe, South-East Europe, and the Middle East-North Africa region.

Gretta regularly speaks at international gatherings and conferences on governance, corruption and asset recovery issues. She is a member of the UNODC expert group on the UNCAC review mechanisms, of the World Economic Forum Partnering Against Corruption Task Force, and participates as expert in the Wolfsberg Group.