Marguerite Julie Charpentier was the daughter of François Philippe Charpentier (1734–1817), a draughtsman and engraver. He invented the process of aquatint engraving and was subsequently named mécanicien du roi, a position which entitled his family to lodgings in the Palais du Louvre. M. J. Charpentier learned the art of drawing from her father and began making clay models during childhood. She took some private lessons from the sculptor Augustin Pajou (1730–1809) but never received an academic training. Her entrance on the Parisian art scene came in 1787 at the early age of seventeen, when she presented a bust of the Virgin Mary and a bas-relief of the Duke of Orleans (unlocated) at the Salon de la Correspondance. Specialising in portraiture, she showed a clear talent in the art of modelling, combining a search for psychological truth and realism in the depiction of details with an elegant dexterity in her surface finishes (Buste d’homme, 1791, Saint-Quentin, Musée Antoine Lécuyer). In 1793 she sent a total of ten works to the Salon, including an Autoportrait (unlocated), thereby firmly establishing herself as a sculptor.

Between 1787 and 1824, forty-one sculptures by M. J. Charpentier were accepted at the Salon. She was one of the few women to pursue an official career as a statue sculptor during the period, attempting to earn a living from her art during the Revolution, the Empire and then the Restoration. From 1806 she received regular public commissions, contributing four reliefs to the decoration of the present-day Vendôme column, and sculpting a marble bas-relief for a fountain in Blois, depicting an allegorical vision of the town (Blois, Square Henri-Lévy). In 1816 and 1821 she made two reliefs, La Chirurgie and La Géographie, for the base of an unrealised project for a monumental fountain at Place de la Bastille, Paris. Her talent as a portraitist saw her hired to furnish the Musée Napoléon (now the Musée du Louvre) with two marble commemorative busts: the architect Pierre Lescot (1814) for the Salle des Fleuves (Versailles, Musée National des Châteaux de Versailles et de Trianon) and the painter Domenichino (1819) as decoration for the gallery (Paris, Musée du Louvre). She was charged with sculpting memorial busts of Colonel François-Louis Morland (1808, work presumed destroyed in the Tuileries fire of 1871, cast preserved at the Château de Versailles), Joseph-Marie Vien (1819, Montpellier, Musée Fabre) and Clémence Isaure (1822, Toulouse, Musée des Augustins).

M. J. Charpentier never married, and lived with her parents and sister Adélaïde at Les Gobelins, her father having been permitted to relocate the family there when the Louvre lodgings were closed during the Revolution. Faced with severe and ongoing financial difficulties, in 1801 she found work at the Muséum d’Histoire Naturelle preparing natural specimens. Alongside her work as a sculptor, she practiced taxidermy for twenty years in that institution, which still counts her plaster busts of Étienne Geoffroy Saint-Hilaire (1802) and Georges Cuvier (1804) amongst the works in its collection. She officially became a salaried employee only at the age of fifty-six, soon after having abandoned sculpture. In 1830, the museum’s administration offered her housing on the first floor of one of its buildings. In 1843 she entered the Salpêtrière women’s hospice, where she died two years later in abject poverty, already forgotten by her contemporaries.