Lelong earned his doctorate in 1941 from the École Normale Supérieure, under the supervision of Paul Montel. On June 5, 1981 Lelong received an honorary doctorate from the Faculty of Mathematics and Science at Uppsala University, Sweden. He was a member of the French Academy of Sciences since 1985.
He married another mathematician, Jacqueline Ferrand, in 1947; they separated in 1977.
- Pierre Lelong at the académie des sciences
- Pierre Lelong at the Mathematics Genealogy Project
- Kosmann-Schwarzbach, Yvette (2015), "Women mathematicians in France in the mid-twentieth century", BSHM Bulletin: Journal of the British Society for the History of Mathematics, arXiv:1502.07597, doi:10.1080/17498430.2014.976804.