Guillaume Poupard is a former student of the Polytechnic School, he is a qualified weapons engineer, and holds a Ph.D. thesis in cryptography under the direction of Jacques Stern at the École normale supérieure in Paris. He is also a graduate of higher education in psychology.
He began his career as an expert then head of the cryptography laboratory of the Central Directorate of Information Systems Security (DCSSI). This management will be transformed in 2009 to become the National Agency for Security Information Systems (ANSSI). He joined in 2006 the Ministry of Defense, still in the field of government cryptography and cyber defense. In November 2010, he became Head of Information Systems Security at the Technical Directorate of the Directorate General of Armaments (DGA), responsible for expertise and technical policy in the field of cybersecurity. On March 27, 2014, he was appointed General Manager of the National Information Systems Security Agency.