He became the first president of the European Atomic Energy Community (Euratom) as chair of the Armand Commission from 1958 to 1959 before he was elected to the Académie Française in 1963.

In 1940–1941 he invented a method for preventing the calcification, furring up, of engine boilers called the Traitement Integral Armand (TIA) water treatment process for steam locomotives.

In 1949, Armand was named the general manager of the SNCF and created the Société du tunnel sous la Manche in 1957.

[1] In the late 1960s, after May 1968 in Paris, Louis Armand was instrumental in helping Christian LeClercq and the Junior Chamber of Commerce of Brussels to start a new European thinktank and membership organization: "L'Entreprise de Demain - Forum for Tomorrow".

"L'Entreprise de Demain - Forum for Tomorrow" soon developed chapters in Denmark, France, Switzerland and the United States, allowing some of the most brilliant minds of the time to address corporate executives and share their views about the future of the world.