A graduate of École Centrale Paris, he holds a DEA (Master of Advanced Studies) in theoretical physics, as well as a Ph.D. in philosophy of science and an accreditation to supervise research (HDR).

[1] He is currently head of the Laboratoire des Recherches sur les Sciences de la Matière (LARSIM), a research laboratory belonging to the CEA and located in Saclay near Paris.

[1] Every Thursday morning he presents a radio chronicle, Le Monde selon Étienne Klein, as well as La Conversation scientifique every Saturday afternoon, on the French public station France Culture.

[9] In August 2024, French media Arrêt sur images revealed that 88 of the 429 pages of the book adapted from his PhD thesis, L’Unité de la physique (2000), contain plagiarized text by Gerald Holton, Lambros Couloubaritsis and other philosophers.

[10] On July 22, 2022, Klein tweeted a photo that he presented as an image of Proxima Centuri, the closest star to our solar system, taken by the James Webb Space Telescope.