Julie Manet was born in Paris, the only child of French painters Berthe Morisot and her husband Eugène Manet, a younger brother of Édouard Manet. In her family's wealthy and cultured household, she was privately tutored and introduced at a very early age to music and art, which she loved. She frequently sat as a model for her mother and other Impressionist artists, including her uncle and Renoir, and is remembered today for the lovely images of her they created. Her father died when she was 5 years old, and her mother 10 years later, after which she lived with cousins under the guardianship of Stéphane Mallarmé.
Her diary, begun at age 14, was later translated and published in English as Growing up with the Impressionists. It provides valuable insights into the lives of French painters of that era, including Renoir, Degas, Monet, and Sisley, as well the 1896 state visit of Tsar Nicholas II of Russia and the Dreyfus Affair. In 1900, Julie married Ernest Rouart, also an artist.