Born in Versaillesat the beginning of the French Revolution, Stéphanie was a great-granddaughter to Claude de Beauharnais and Renée Hardouineau who were married in La Rochelle during 1713. Their oldest son was François de Beauharnais, Marquess de la Ferte-Beauharnais who served as a governor of Martinique. Their younger son was Claude de Beauharnais, 1st Count des Roches-Baritaud, Stephanie's paternal grandfather. Claude was married in 1753 to Marie Anne Françoise Mouchard, known in poetry as Fanny de Beauharnais. Their oldest son was Claude de Beauharnais, 2nd Count des Roches-Baritaud. In 1783 the 2nd Count married Claudine Françoise de Lezay. The marriage resulted in the birth of first her older brother Alberic de Beauharnais and then Stephanie herself. Her father was remarried in 1799 to Suzanne Fortin-Duplessis. The second marriage resulted in the birth of her half-sister Joséphine de Beauharnais, Marchioness de Quiqueran-Beaujeu. The fates of her family however would be defined by another Joséphine. On December 13, 1779 Alexandre, Vicomte de Beauharnais, first cousin of her father, was married to Joséphine Tascher de la Pagerie. On July 23, 1794, Alexandre was guillotined. Joséphine had affairs with several influential figures of the French Directory, including Paul François Jean Nicolas Barras. The latter would introduce her to his recent favorite Napoléon Bonaparte. Napoléon soon started courting her. On March 9, 1796 they were married. General Napoléon Bonaparte was now stepfather to Eugène de Beauharnais and Hortense de Beauharnais, second cousins of Stephanie. As his prominence and wealth continued to rise, Napoléon found himself being de factopatron to both the Bonaparte and the de Beauharnais families. Stephanie would soon see her patron rise to become First Consul of France. Her "uncle" crowned himself Emperor of the French on December 2, 1804. As a prominent member of the new Imperial Family, Stephanie held residence in the Tuileries Palace. Her new status allowed her to live a rather luxurious life. She would soon however have to depart both the Palace and France. This was a consequence of Napoleon's effort to secure an alliance with the Prince-elector of Baden. The alliance was to be secured through a marriage between the descendants of the two sovereigns, connecting the two dynasties. The Prince-Elector was to be represented by his grandson. Napoleon on the other hand lacked legitimate descendants of his own. He adopted Stephanie and named her "Princesse Française" with the style of Imperial Highness. The marriage took place in Paris on April 8, 1806. On July 25, 1806 her new grandfather-in-law was named Karl Friedrich, Grand Duke of Baden. By most accounts the arranged marriage was not particularly successful. Her husband was determined to continue living as a bachelor. He set residence in Karlsruhe. She was allowed to settle separately in Mannheim. Even the official complaints by the Emperor did not resolve this situation. The Grand Duke offered Schwetzingen to be their common summer residence. But only Stephanie accepted the offer. The situation changed somewhat when it became evident that the aging Grand Duke would not live much longer. The couple apparently reconciled in an effort to produce heirs for the throne.
Children
On June 10, 1811, Stephanie's husband, Karl succeeded his grandfather as Grand Duke of Baden. He and Grand Duchess Stephanie would have five children:
Princess Luise Amelie Stephanie of Baden. She was married on November 30, 1830 to Gustav, Prince of Vasa.
Unnamed son. One theory suspects the dead unnamed child to be unrelated to her and her actual son to be Kaspar Hauser. Although some authors have argued that this was not the case, "the silly fairytale, which to this day moves many pens and has found much belief, was fully disproved in Otto Mittelstädt's book on Kaspar Hauser and his Baden Princedom." The idea has remained current in some circles to this day.
Among her descendants are the former Kings of Romania and former King of Yugoslavia, the present King of the Belgians, the present Grand Duke of Luxembourg and the present Sovereign Prince of Monaco. The Grand Duke died on December 8, 1818. Stephanie remained a widow for the rest of her long life. She was reportedly a devoted mother to her three daughters. Her residence in Mannheim became a popular Salon for artists and intellectuals. Stephanie died in Nice, France at the age of 71, in 1860, 41 years after her husband.