He gained his secondary education in Auxerre and the Lycée Pierre Corneille in Rouen[1] before entering the École polytechnique, Paris in 1801, only for his studies to be impeded by poor health.

[2] He began studying medicine, but gave this up, possibly because of a lack of financial means,[2] to concentrate on science, working under the direction of Louis Jacques Thénard.

In chemistry, he contributed to knowledge on: Dulong also discovered the dangerously sensitive nitrogen trichloride in 1811, losing three fingers and an eye in the process.

[5] In 1815, Dulong collaborated for the first time with Alexis Thérèse Petit, in publishing a paper on heat expansion.

[7] In 1820, Dulong succeeded Petit, who retired due to poor health,[6] as professor of physics at École polytechnique.

He was credited with an instinctive scientific intuition, a power of premature invention, certain presages of an assured future that everyone foresaw and even desired, so great was the benevolence which he inspired.

He worked slowly but with certainty, with a continuity and a power of will that nothing stopped, I should say with a courage that no danger could push back.

In the absence of that vivacity of the mind which invents easily, but likes to rest, he had the sense of scientific exactness, the gusto for precision experiments, the talent of combining them, the patience of completing them, and the art, unknown before him, to carry them to the limits of accuracy[.

Petit had more mathematical tendency, Dulong was more experimental; the first carried in the work more brilliant easiness, the second more continuity; One represented imagination, the other reason, which moderates and contains it.Dulong was noted both for his devotion to science and the stolid, almost casual, bravery he displayed in prosecuting his experiments.

One such experiment involved the construction of a glass tubular apparatus atop the tower at the Abbey of Saint Genevieve.