Konstantinos Maniatopoulos has had a long professional career, serving as the Director-General for Energy at the European Commission, as the Chairman and CEO of an Oil Company, and as Chairman or Member of the Board of Directors of various national and private organizations and companies in Greece (TAIPED, ETAD, Piraeus Port Authority, Athens International Airport, MOD, EKO, OSE, Kantor, etc.).

He has represented the European Commission at the Governing Boards of the International Energy Agency (IEA) and the International Atomic Energy Agency (IAEA), was the coordinator of the processes establishing the Energy Charter, and is a member of the Oxford Energy Club and the Club de Nice – Energie et Géopolitique.

As an advisor to DEI (Public Power Corporation), DEPA (Public Gas Corporation), the Ministry of Energy, consulting firms, and an executive in companies, he has been active in the energy sector, particularly in petroleum, business organization and management, investments, and international relations. He has also been a member of various professional associations and chambers of commerce.