Marie-Gabrielle came from a modest background and her previous background and artistic training is unknown, but in 1781 she became the pupil of the French painter Adelaide Labille-Guiard in Paris. In eighteenth-century France, the Royal Academy of Art was responsible for training artists and exhibiting artworks at the Salon that glorified heroic values promoted by the Bourbon patriarchy. Until the French Revolution, the Royal Academy of Art in Paris was the central institution for official artistic practice, and limited its number of female students to four at a time.
In 1781, twenty-year-old Capet moved to Paris to become the student of Adélaïde Labille-Guiard (1749-1803), a Neoclassical artist who was admitted to the Academy in 1783.
Capet showed her early work at the Exposition de la Jeunesse, and later exhibited at the Salon when it was opened to all artists after the French Revolution. Her body of work included miniature paintings, oil paintings, and pastels, which were praised for their virtuoso draftsmanship and use of color.
Many of her pastel paintings were portraits, though by 1808 she was regarded as a history painter in her own right. Capet and Labille-Guiard not only enjoyed a professional relationship, but were also close family friends.
Capet would move in with her teacher at the Louvre until Labille-Guiard"s death.
Even after Adélaïde Labille-Guiard married the painter François Vincent in 1799, Capet continued to live in their home. Mars, and Jean-Antoine Houdon. She died in Paris in 1818.
She died in Paris in 1818.
She counted among other customers several members of the royal family, and other members of Paris society, such as the lawyer Pierre-Nicolas Berryer and the playwright Joseph Chénier. At that time the Academy had limited the members of women painters to only four woman members.