Émilie de Breteuil was a rather awkward child, and so she was given lessons in fencing, riding, and gymnastics in an attempt to improve her coordination. She was remarkably well educated for the time, and by the age of twelve she was fluent in Latin, Italian, Greek and German. She received education in mathematics, literature, and even science as well. She also liked to dance, was a passable performer on the harpsichord, sang opera, and was an amateur actress.

Marriage and liaisons
Émilie de Breteuil was married on 20 June 1725 to the Marquis Florent-Claude du Chastellet, and thus became Marquise du Chastellet (the spelling Châtelet was introduced by Voltaire, and has now become standard). The Marquis was a military man and governor of Semur-en-Auxois in Burgundy. The marriage was arranged, and they had little in common, but did not openly fight often. Émilie du Châtelet had three children, and, considering her marital responsibility completed, they agreed to live separate lives. In the upper classes of France at the time, it was standard for both the husband and wife to have a lover.

Émilie du Châtelet had had three love affairs before she met Voltaire. At the age of twenty-four, she had an affair with the Duc de Richelieu that lasted for a year and a half. The Duc was interested in literature and philosophy, and Châtelet was one of the few women who could converse with him on his own level. She read every book of consequence, attended the theater regularly, and enjoyed intellectual debate. Châtelet expressed an interest in Isaac Newton, and Richelieu encouraged her to take lessons in higher mathematics to better understand his theories.

Châtelet invited Voltaire to live in her country house at Cirey in Lorraine, and she became his long-time companion (under the eyes of her tolerant husband). There she studied physics and mathematics and published scientific articles and translations. Her translation of Newton's Principia Mathematica is still regarded as the standard version in France. Her greatest discovery was the demonstration that the kinetic energy of an object is a function of the square of its velocity.

Moreau de Maupertuis, a member of the Academy of Sciences, became Châtelet's tutor in geometry. He was a mathematician, astronomer and physicist, and supported Newton's theories, which were the topic of hot debate at the Academy.

Châtelet's last affair proved to be fatal. In her early 40s, she had an affair with a young soldier and became pregnant. Fraught with premonitions of dying in childbirth, Châtelet bore the child, but died six days later from an embolism at the age of 43. A great mind of the 18th century was prematurely lost.