After obtaining a Master of Science in Economics at the Catholic University of Louvain in Belgium, Carlo Thelen joined the Luxembourg Chamber of Commerce in 1996 as an Economic Adviser.

In August 2003, he joined the Executive Committee of the Chamber of Commerce and in January 2004, he became Director of International Affairs. In January 2014 he was nominated Director General.

Until 2019, he was also the Chief Economist of the Chamber of Commerce, each year preparing and presenting the most important official opinion of the Chamber of Commerce: the opinion on the state budget.

Carlo Thelen is also the author of a notable expert blog that highlights current important socio-economic questions, as well as articles and strategic papers published by the Chamber of Commerce. He also represents the Chamber of Commerce in different working groups and councils in Luxembourg institutions and organisations, is in charge of strategic papers, studies, surveys and statistics, research and innovation, documentation and literature on economics, and regularly gives advice and consultations on these subjects.

In addition to his economic expertise, Carlo Thelen has extensive experience in commercial and economic advocacy as he regularly participates in economic missions abroad where he promotes the Luxembourg economy and businesses.