Claude Monet was born on 14 November 1840 on the 5th floor of 45 rue Laffitte, in the ninth arrondissement of Paris. He was the second son of Claude Adolphe Monet and Louise Justine Aubrée Monet, both of them second-generation Parisians. On 20 May 1841, he was baptized in the local parish church, Notre-Dame-de-Lorette, as Oscar-Claude, but his parents called him simply Oscar. In 1845, his family moved to Le Havre in Normandy. His father wanted him to go into the family grocery business, but Monet wanted to become an artist. His mother was a singer. On the first of April 1851, Monet entered Le Havre secondary school of the arts. Locals knew him well for his charcoal caricatures, which he would sell for ten to twenty francs. Monet also undertook his first drawing lessons from Jacques-François Ochard, a former student of Jacques-Louis David. On the beaches of Normandy in about 1856/1857, he met fellow artist Eugène Boudin, who became his mentor and taught him to use oil paints. Boudin taught Monet "en plein air" (outdoor) techniques for painting. Both received the influence of Johan Barthold Jongkind. On 28 January 1857, his mother died. At the age of sixteen, he left school and went to live with his widowed childless aunt, Marie-Jeanne Lecadre.

When Monet traveled to Paris to visit the Louvre, he witnessed painters copying from the old masters. Having brought his paints and other tools with him, he would instead go and sit by a window and paint what he saw. Monet was in Paris for several years and met other young painters who would become friends and fellow impressionists; among them was Édouard Manet.

In June 1861, Monet joined the First Regiment of African Light Cavalry in Algeria for a seven-year commitment, but, two years later, after he had contracted typhoid fever, his aunt Marie-Jeanne Lecadre intervened to get him out of the army if he agreed to complete an art course at an art school. It is possible that the Dutch painter Johan Barthold Jongkind, whom Monet knew, may have prompted his aunt on this matter. Disillusioned with the traditional art taught at art schools, in 1862 Monet became a student of Charles Gleyre in Paris, where he met Pierre-Auguste Renoir, Frédéric Bazille and Alfred Sisley. Together they shared new approaches to art, painting the effects of light en plein air with broken color and rapid brushstrokes, in what later came to be known as Impressionism.

Monet's Camille or The Woman in the Green Dress (La femme à la robe verte), painted in 1866, brought him recognition and was one of many works featuring his future wife, Camille Doncieux; she was the model for the figures in Women in the Garden of the following year, as well as for On the Bank of the Seine, Bennecourt, 1868. Shortly thereafter, Camille became pregnant and gave birth to their first child, Jean.

After the outbreak of the Franco-Prussian War (19 July 1870), Monet took refuge in England in September 1870. While there, he studied the works of John Constable and Joseph Mallord William Turner, both of whose landscapes would serve to inspire Monet's innovations in the study of color. In the Spring of 1871, Monet's works were refused authorisation for inclusion in the Royal Academy exhibition. In May 1871, he left London to live in Zaandam, in the Netherlands, where he made twenty-five paintings (and the police suspected him of revolutionary activities). He also paid a first visit to nearby Amsterdam. In October or November 1871, he returned to France. Monet lived from December 1871 to 1878 at Argenteuil, a village on the right bank of the Seine river near Paris, and a popular Sunday-outing destination for Parisians, where he painted some of his best known works. In 1874, he briefly returned to Holland.

In 1872, he painted Impression, Sunrise (Impression, soleil levant) depicting a Le Havre landscape. It hung in the first Impressionist exhibition in 1874 and is now displayed in the Musée Marmottan Monet in Paris. From the painting's title, art critic Louis Leroy coined the term "Impressionism", which he intended as disparagement but which the Impressionists appropriated for themselves. Also in this exhibition was a painting titled Boulevard des Capucines, a painting of the boulevard done from the photographer Nadar's apartment at no. 35. There were, however, two paintings by Monet of the boulevard: one is now in the Pushkin Museum in Moscow, the other in the Nelson-Atkins Museum of Art in Kansas City. It has never become clear which painting appeared in the groundbreaking 1874 exhibition, though more recently the Moscow picture has been favoured.

Monet and Camille Doncieux had married just before the war (28 June 1870) and, after their excursion to London and Zaandam, they had moved to Argenteuil, in December 1871. It was during this time that Monet painted various works of modern life. Camille became ill in 1876. They had a second son, Michel, on 17 March 1878, (Jean was born in 1867). This second child weakened her already fading health. In that same year, he moved to the village of Vétheuil. On 5 September 1879, Camille Monet died of tuberculosis at the age of thirty-two; Monet painted her on her death bed. After several difficult months following the death of Camille, a grief-stricken Monet (resolving never to be mired in poverty again) began in earnest to create some of his best paintings of the 19th century. During the early 1880s, Monet painted several groups of landscapes and seascapes in what he considered to be campaigns to document the French countryside. His extensive campaigns evolved into his series' paintings.

Camille Monet had become ill with tuberculosis in 1876. Pregnant with her second child she gave birth to Michel Monet in March 1878. In 1878 the Monets temporarily moved into the home of Ernest Hoschedé, (1837 - 1891), a wealthy department store owner and patron of the arts. Both families then shared a house in Vétheuil during the summer. After her husband (Ernest Hoschedé) became bankrupt, and left in 1878 for Belgium, and after the death of Camille Monet in September 1879, and while Monet continued to live in the house in Vétheuil; Alice Hoschedé helped Monet to raise his two sons, Jean and Michel, by taking them to Paris to live alongside her own six children. They were Blanche Hoschedé Monet, (She eventually married Jean Monet), Germaine, Suzanne Hoschedé, Marthe, Jean-Pierre, and Jacques. In the spring of 1880, Alice Hoschedé and all the children left Paris and rejoined Monet still living in the house in Vétheuil. In 1881, all of them moved to Poissy, which Monet hated. In April 1883, looking out the window of the little train between Vernon and Gasny, he discovered Giverny. They then moved to Vernon, then to a house in Giverny, Eure, in Upper Normandy, where he planted a large garden and where he painted for much of the rest of his life. Following the death of her estranged husband, Alice Hoschedé married Claude Monet in 1892.

At the beginning of May 1883, Monet and his large family rented a house and 2 acres (8,100 m²) from a local landowner. The house was situated near the main road between the towns of Vernon and Gasny at Giverny. There was a barn that doubled as a painting studio, orchards and a small garden. The house was close enough to the local schools for the children to attend and the surrounding landscape offered many suitable motifs for Monet's work. The family worked and built up the gardens and Monet's fortunes began to change for the better as his dealer Paul Durand-Ruel had increasing success in selling his paintings. By November 1890, Monet was prosperous enough to buy the house, the surrounding buildings and the land for his gardens. During the 1890s, Monet built a greenhouse and a second studio, a spacious building well lit with skylights. Beginning in the 1880s and 1890s through the end of his life in 1926, Monet worked on "series" paintings, in which a subject was depicted in varying light and weather conditions. His first series exhibited as such was of Haystacks, painted from different points of view and at different times of the day. Fifteen of the paintings were exhibited at the Galerie Durand-Ruel in 1891. He later produced several series of paintings including: Rouen Cathedral, Poplars, the Parliament, Mornings on the Seine, and the Water Lilies that were painted on his property at Giverny.

Monet was exceptionally fond of painting controlled nature: his own gardens in Giverny, with its water lilies, pond, and bridge. He also painted up and down the banks of the Seine, producing paintings such as Break-up of the ice on the Seine.

He wrote daily instructions to his gardening staff, precise designs and layouts for plantings, and invoices for his floral purchases and his collection of botany books. As Monet's wealth grew, his garden evolved. He remained its architect, even after he hired seven gardeners.

Between 1883 and 1908, Monet traveled to the Mediterranean, where he painted landmarks, landscapes, and seascapes, such as Bordighera. He painted an important series of paintings in Venice, Italy, and in London he painted two important series — views of Parliament and views of Charing Cross Bridge. His second wife, Alice, died in 1911 and his oldest son Jean, who had married Alice's daughter Blanche, Monet's particular favourite, died in 1914. After his wife died, Blanche looked after and cared for him. It was during this time that Monet began to develop the first signs of cataracts.

During World War I, in which his younger son Michel served and his friend and admirer Clemenceau led the French nation, Monet painted a series of weeping willow trees as homage to the French fallen soldiers. In 1923, he underwent two operations to remove his cataracts: the paintings done while the cataracts affected his vision have a general reddish tone, which is characteristic of the vision of cataract victims. It may also be that after surgery he was able to see certain ultraviolet wavelengths of light that are normally excluded by the lens of the eye, this may have had an effect on the colors he perceived. After his operations, he even repainted some of these paintings, with bluer water lilies than before the operation.

Monet died of lung cancer on 5 December 1926 at the age of 86 and is buried in the Giverny church cemetery. Monet had insisted that the occasion be simple; thus only about fifty people attended the ceremony.

His famous home, garden and waterlily pond were bequeathed by his son Michel, his only heir, to the French Academy of Fine Arts (part of the Institut de France) in 1966. Through the Fondation Claude Monet, the house and gardens were opened for visit in 1980, following restoration. In addition to souvenirs of Monet and other objects of his life, the house contains his collection of Japanese woodcut prints. The house is one of the two main attractions of Giverny, which hosts tourists from all over the world.