Under Leray's tutorship de Gosson completed a Habilitation à Diriger des Recherches en Mathématiques at the University of Paris 6 (1992).

Basil Hiley wrote a foreword to de Gosson's book The Principles of Newtonian and Quantum Mechanics (Imperial College Press, London).

[4][5] Maurice de Gosson has held longer visiting positions at Yale University,[6][7] University of Colorado in Boulder (Ulam Visiting Professor) ,[8] University of Potsdam, Albert-Einstein-Institut (Golm), Max-Planck-Institut für Mathematik (Bonn), Université Paul Sabatier (Toulouse), Jacobs Universität (Bremen) Maurice de Gosson was the first to prove that Mikhail Gromov's symplectic non-squeezing theorem (also called the Principle of "the Symplectic Camel") allowed the derivation of a classical uncertainty principle formally totally similar to the Robertson–Schrödinger uncertainty relations (i.e. the Heisenberg inequalities in a stronger form where the covariances are taken into account).

[15][16] Together with G. Dennis and Basil Hiley, de Gosson laid out examples of how the quantum blob can be seen as a "blow-up" of a particle in phase space.

To demonstrate this, they picked up on "Fermi's trick"[17] which allows identifying an arbitrary wavefunction as a stationary state for some Hamiltonian operator.