He received the SIAM's John von Neumann Lecture prize in 1986 and numerous other distinctions.

He became a professor of mathematics at the University of Nancy, the Faculty of Sciences of Paris, and the École Polytechnique.

In 1979, he was appointed director of the Institut National de la Recherche en Informatique et Automatique (INRIA), where he taught and promoted the use of numerical simulations using finite elements integration.

Throughout his career, Lions insisted on the use of mathematics in industry, with a particular involvement in the French space program, as well as in domains such as energy and the environment.

[2][3] He has left a considerable body of work, among this more than 400 scientific articles, 20 volumes of mathematics that were translated into English and Russian, and major contributions to several collective works, including the 4000 pages of the monumental Mathematical analysis and numerical methods for science and technology (in collaboration with Robert Dautray), as well as the Handbook of numerical analysis in 7 volumes (with Philippe G. Ciarlet).