Marie Josèphe Rose Tascher de La Pagerie was born in Les Trois-Îlets, Martinique to a wealthy white Creole family that owned a sugarcane plantation, which is now a museum. She was the eldest daughter of Joseph-Gaspard Tascher (1735–1790), knight, Seigneur de (lord of) la Pagerie, lieutenant of Troupes de Marine, and his wife, the former Rose-Claire des Vergers de Sannois (1736–1807), whose maternal grandfather, Anthony Brown, may have been Irish.

The family struggled financially after hurricanes destroyed their estate in 1766. Edmée (French, Desirée), Joséphine's paternal aunt, had been the mistress of François, Vicomte de Beauharnais, a French aristocrat. When François's health began to fail, Edmée arranged the advantageous marriage of her niece, Catherine-Désirée, to François's son Alex Andre. This marriage would be highly beneficial for the Tascher family, because it would keep the Beauharnais money in their hands; however, 12-year-old Catherine died on 16 October 1777, before she could leave Martinique for France. In Service to their aunt Edmée's goals, Catherine was replaced by her older sister, Joséphine.

In October 1779, Joséphine went to France with her father. She married Alex Andre on 13 December 1779, in Noisy-le-Grand. They had two children: a son, Eugène de Beauharnais (1781–1824), and a daughter, Hortense de Beauharnais (1783–1837) (who later married Napoleon's brother Louis Bonaparte in 1802). Joséphine and Alexandre's marriage was not a happy one, leading to a court-ordered separation during which she and the children lived at Alexandre's expense in the Pentemont Abbey. On 2 March 1794, during the Reign of Terror, the Committee of Public Safety ordered the arrest of her husband. He was jailed in the Carmes prison in Paris. Considering Joséphine as too close to the counter-revolutionary financial circles, the Committee ordered her arrest on 18 April 1794. A warrant of arrest was issued against her on 2 Floréal, year II (April 21, 1794), and she was imprisoned in the Carmes prison until 10 Thermidor, year II (28 July 1794).

Her husband was accused of having poorly defended Mainz in July 1793, and being considered an aristocratic "suspect", was sentenced to death and guillotined, with his cousin Augustin, on 23 July 1794, on the Place de la Révolution (today's Place de la Concorde) in Paris. Joséphine was freed five days later, thanks to the fall and execution of Robespierre, which ended the Reign of Terror. On 27 July 1794 (9 Thermidor), Tallien arranged the liberation of Thérèse Cabarrus, and soon after that of Joséphine. In June 1795, a new law allowed her to recover the possessions of Alex Andre.

Madame de Beauharnais had affairs with several leading political figures, including Paul François Jean Nicolas Barras. In 1795, she met Napoleon Bonaparte, six years her junior, and became his mistress. In a letter to her in December, he wrote, "I awake full of you. Your image and the memory of last night’s intoxicating pleasures has left no rest to my senses." In January 1796, Napoleon Bonaparte proposed to her and they were married on 9 March. Until meeting Bonaparte, she was known as Rose, but Bonaparte preferred to call her Joséphine, the name she adopted from then on.

Joséphine, left behind in Paris, in 1796 began an affair with a handsome Hussar lieutenant, Hippolyte Charles. Rumors of the affair reached Napoleon; he was infuriated, and his love for her changed entirely.

The marriage was not well received by Napoleon's family, who were shocked that he had married an older widow with two children. His mother and sisters were especially resentful of Joséphine, as they felt clumsy and unsophisticated in her presence. Two days after the wedding, Bonaparte left Paris to lead a French army into Italy. During their separation, he sent her many love letters. In February 1797, he wrote: “You to whom nature has given spirit, sweetness, and beauty, you who alone can move and rule my heart, you who know all too well the absolute empire you exercise over it!”

In 1798, Napoleon led a French army to Egypt. During this campaign, Napoleon started an affair of his own with Pauline Fourès, the wife of a junior officer, who became known as "Napoleon's Cleopatra." The relationship between Joséphine and Napoleon was never the same after this. His letters became less loving. No subsequent lovers of Joséphine are recorded, but Napoleon had sexual affairs with several other women. In 1804, he said, "Power is my mistress."

In 1799 while Napoleon was in Egypt, Josephine purchased the Chateau de Malmaison. She had it landscaped in an “English” style, hiring landscapers and horticulturalists from the United Kingdom. These included Thomas Blaikie, a Scottish horticultural expert, another Scottish gardener, Alexander Howatson, the Botanist, Ventenat, and the horticulturist, Andre Dupont. The rose garden was begun soon after purchase; inspired by Dupont’s love of roses. Josephine took a personal interest in the gardens and the roses, and learned a great deal about botany and horticulture from her staff. Josephine wanted to collect all known roses so Napoleon ordered his warship commanders to search all seized vessels for plants to be forwarded to Malmaison. Pierre-Joseph Redouté was commissioned by her to paint the flowers from her gardens. Les Roses was published 1817–20 with 168 plates of roses; 75–80 of the roses grew at Malmaison. The English nurseryman Kennedy was a major supplier, despite England and France being at war, his shipments were allowed to cross blockades. Specifically, when Hume’s Blush Tea-Scented China was imported to England from China, the British and French Admiralties made arrangements in 1810 for specimens to cross naval blockades for Josephine’s garden. Sir Joseph Banks, Director of the Royal Botanic Gardens, Kew, also sent her roses. The general assumption is that she had about 250 roses in her garden when she died in 1814. Unfortunately the roses were not catalogued during her tenure. There may have been only 197 rose varieties in existence in 1814, according to calculations by Jules Gravereaux of Roseraie de l’Haye. There were 12 species, about 40 centifolias, mosses and damasks, 20 Bengals, and about 100 gallicas. The Botanist Claude Antoine Thory, who wrote the descriptions for Redouté’s paintings in Les Roses, noted that Josephine’s Bengal rose R. indica had black spots on it. She produced the first written history of the cultivation of roses, and is believed to have hosted the first rose exhibition, in 1810.

In December 1800, Joséphine was nearly killed in the Plot of the rue Saint-Nicaise, an attempt on Napoleon's life with a bomb planted in a parked cart. On December 24, she and Napoleon went to see a performance of Joseph Haydn's Creation at the Opéra, accompanied by several friends and family. The party travelled in two carriages. Joséphine was in the second, with her daughter, Hortense; her pregnant sister-in-law, Caroline Murat; and General Jean Rapp. Joséphine had delayed the party while getting a new silk shawl draped correctly, and Napoleon went ahead in the first carriage. The bomb exploded as her carriage was passing. The bomb killed several bystanders and one of the carriage horses, and blew out the carriage's windows; Hortense was struck in the hand by flying glass. There were no other injuries and the party proceeded to the Opéra.

Henry Breen also received confirmation from Josephine's former slave nanny called "Dede", who claimed she nursed Josephine at La Cauzette. Josephine's baptism was administered by Pere Emmanuel Capuchin at Trois-Ilets but he has only stated she had been baptized there but not born. Dom Daviot, parish priest in Gros Islet, wrote a letter to one of his friends in Haute-Saône in 1802 in which he states: "it is in the vicinity of my parish that the wife of the first consul was born," at the time, Paix Bouche was a part of Castries; he asserts that he was well acquainted with Josephine's cousin who was a parishioner.

The coronation ceremony, officiated by Pope Pius VII, took place at Notre Dame de Paris, on 2 December 1804. Following a pre-arranged protocol, Napoleon first crowned himself, then put the crown on Joséphine's head, proclaiming her Empress.

When after a few years it became clear she could not have a child, Napoleon, while still loving Joséphine, began to think very seriously about the possibility of divorce. The final die was cast when Joséphine's grandson Napoléon Charles Bonaparte who had been declared Napoleon's heir, died of croup in 1807. Napoleon began to create lists of eligible princesses. At dinner on 30 November 1809, he let Joséphine know that—in the interest of France—he must find a wife who could produce an heir.

Joséphine agreed to the divorce so the Emperor could remarry in the hope of having an heir. The divorce ceremony took place on 10 January 1810 and was a grand but solemn social occasion, and each read a statement of devotion to the other.

In March 1811 Marie Louise delivered a long-awaited heir, to whom Napoleon gave the title "King of Rome". Two years later Napoleon arranged for Joséphine to meet the young Prince "who had cost her so many tears".

Joséphine died in Rueil-Malmaison on 29 May 1814, soon after walking with Tsar Alexander in the gardens of Malmaison. She was buried in the nearby church of Saint Pierre-Saint Paul in Rueil. Her daughter Hortense is interred near her.

Henry H. Breen, First Mayor of Castries, published The History of St. Lucia in 1844 and stated on page 159 that:

In 1859 Napoleon III commissioned a statue of Josephine for La Savane Park in downtown Fort-de-France, Martinique. In 1991 it was decapitated and shortly afterwards spattered with red paint. These acts were said to be for Josephine's alleged role in convincing Napoleon to reinstitute slavery in the French colonies. (Although in fact Martinique, under first Royalist, then English, rule never accepted the emancipation degree issued by the Revolutionary government.) The head has never been found.

Time Journalist Nathalie Alexandria Kotchoubey de Beauharnais, was a direct descendant of Joséphine through her son Eugène and the Russian line founded by Josephine's grandson Maximilian de Beauharnais, 3rd Duke of Leuchtenberg. She married André Laguerre, longtime managing Editor of Sports Illustrated in 1955 and had two daughters, Michèle and Claudine.

Galliano said that his inspiration was dressing the pregnant rock star Madonna — and then thinking "Empress Josephine."

Brenner and Scanniello call her the "Godmother of modern rosomaniacs" and attribute her with our modern style of vernacular cultivar names as opposed to Latinized, pseudo-scientific cultivar names. For instance, R. alba incarnata became "Cuisse de Nymphe Emue" in her garden. After Josephine’s death in 1814 the house was vacant at times, the garden and house ransacked and vandalised, and the garden’s remains were destroyed in a battle in 1870. The rose 'Souvenir de la Malmaison' appeared in 1844, 30 years after her death, named in her honor by a Russian Grand Duke planting one of the first specimens in the Imperial Garden in St. Petersburg.