Daughter of a landlord father and a mother of independent means, Éléonore Légerot married merchant Pierre-Joseph-Augustin Escallier in 1846. She studied in Dijon with painter and ceramicist Jules-Claude Ziegler (1804-1856) and made her debut at the Salon in 1857 with the pieces Le Vase de fleurs and Les Iris. Until 1880 she regularly exhibited still lifes of flowers, fruit (Pêches et raisins du Jura in 1872) and animals (Un faisan in 1864), one figure (La Jeune fille au poisson in 1865) and decorative panels (L’Étang and Le Jardin  in 1861).
In 1858 she applied for the position of director of a drawing school for women that the Société des Amis des Arts de Dijon planned to open. She later went on to teach flower painting and decoration at the Imperial School for young girls. Her daughter Marguerite (1854-1945), who was also her pupil, began exhibiting at the Salon in 1877. In 1860 E. Escallier won a silver medal at the Exposition de Troyes. In 1862 she was invited to exhibit at the Salon des Amis des Arts in Besançon and in 1869 at the Salon des Amis des Arts in Bordeaux. While she mainly specialised in flowers and fruit, she also painted several portraits around that time (Portrait de Marie Feuvrier à vingt-quatre ans and Portrait of Madame Dugné, née Paffeney, à vingt ans, Musée des Beaux-Arts, Dole).

Throughout the 1860s and into the early 1870s, she worked at the decorative pottery workshop of Théodore Deck (1823-1891). Inspired by Japanese decorative arts, the works she presented at the 1867 World’s Fair on behalf of the Deck manufacture were purchased by the Paris museum of decorative arts and the South Kensington Museum (today’s Victoria & Albert Museum), London. Her fine ceramic dish Perroquet sur une branche de cerisier (1871) is a prominent example of this collaboration.

E. Escallier’s life was marked by her thirst for recognition and her will to make a living from her art. In 1863 she exhibited a self-portrait at the Salon. In it she depicts herself at work, painting a vase and surrounded with flowers. In 1865 and 1866 she wrote to Count van Nieuwerkerke, the intendant of the fine arts department of the Emperor’s Household, to request the formal recognition of her work and acquisitions that would enable her to support herself: “Each year, despite waiting for success that is too long to come, I fight despondency off and send in serious works for which I have spared no effort to deserve the attention of the jury and official rewards.” She insisted that her family depended on her income. Two of her canvases, Fleurs and Vase de fleurs were subsequently acquired and deposited in the Saint-Étienne and Lons-le-Saunier museums. A third piece, Les Chrysanthèmes, was purchased in 1869, followed by Pêches et raisins du Jura in 1872. On 1 May 1869 La Revue des deux mondes devoted an article to her: “Mme Éléonore Escallier, who has remained unknown or little-known to this day, has now stood out with a success. She paints with brilliance and grace, with broad and powerful workmanship, and above all … she draws flowers like figures, as a classic artist and worthy student of Ziegler would.” On 12 April 1872 Louis Ernault wrote of her in Le Constitutionnel: “Mme Escallier is the queen of flowers.”
After winning the medal of honour at the 1868 Salon for her two ceramics Fleurs et oiseaux, she offered her services to the Manufacture Impériale de Sèvres, insisting on her experience, reputation and recent recognition. She was rejected at first but renewed her offer in 1871 and, in 1874, with the support of T. Deck, who was then a member of the development commission of the Manufacture, and of Jules Champfleury, the Manufacture’s head of collections, she was finally hired as a painter. She created models and learnt new techniques, particularly hard-paste porcelain and pâte-sur-pâte. The Vase de la Ville de Paris she presented at the 1878 World’s Fair and at the Ministry of Foreign Affairs achieved great success. In 1885 she received a gold medal at the Antwerp World’s Fair.

E. Escallier received her first state commission in 1874 and created six overdoors depicting flowers and emblems for the Salons de l’Aurore and the museums of the Palais de la Légion d’Honneur. The Rococo inspiration of the pieces demonstrates her adaptation to each location’s style. She received a second commission in 1878 for a decorative tapestry cartoon, Le Printemps (Spring), completed in 1880 and woven by the Manufacture Nationale de Beauvais for the main staircase of the Palais du Luxembourg. The piece was eventually donated to the French embassy in Berlin in 1887.
Following her death in 1888, a retrospective exhibition of her works was held at the Manufacture de Sèvres: “The administration wishes to pay tribute to an artist who never ceased finding ways of creating new styles of lines and decorative ornamentation” (Le Temps, 16 September 1888). Critic Arsène Alexandre wrote: “Here is a woman, a true artist who, upon taking up decoration, distinguished herself immediately amidst her fellow workers. Compare the few vases that Mme Escalier [sic] made in Sèvres with most of their counterparts and you will find originality and grace on the one hand and dryness and dispassion on the other” (“La semaine artistique”, Paris, 1 August 1888).