Flaubert was born in December 12, 1821, in Rouen, Seine-Maritime, in the Haute-Normandie region of France. He was the second son of Achille-Cleophas Flaubert (1784–1846), a surgeon, and Anne Justine Caroline (nee Fleuriot) (1793–1872). He began writing at an early age, as early as eight according to some sources. He was educated in his native city and did not leave it until 1840, when he went to Paris to study law.

In Paris, he was an indifferent student and found the city distasteful. He made a few acquaintances, including Victor Hugo. Towards the close of 1840, he travelled in the Pyrenees and Corsica. In 1846, after an attack of epilepsy, he left Paris and abandoned the study of law.
After leaving Paris, Flaubert returned to Croisset, close to Rouen, and lived with his mother. Their home near the Seine became Flaubert`s home for the rest of his life. Flaubert never married. From 1846 to 1854, he had an affair with the poet Louise Colet (his letters to her survive). According to his biographer Émile Faguet, his affair with Louise Colet was his only serious romantic relationship. He sometimes visited prostitutes. Eventually, the end of his affair with Louise Colet led Flaubert to lose interest in romance and seek platonic companionship, particularly with other writers.
With his lifelong friend Maxime du Camp, he traveled in Brittany in 1846, and to Greece and Egypt in 1849. After 1850, Flaubert lived in Croisset with occasional visits to Paris and England, where he had a mistress. He visited Carthage in 1858 to conduct research for his novel Salammbo.

Flaubert was a tireless worker and often complained in his letters to friends about the strenuous nature of his work. He was close to his niece, Caroline Commanville, and had a close friendship and correspondence with George Sand. He occasionally visited Parisian acquaintances, including Emile Zola, Alphonse Daudet, Ivan Turgenev, and Edmond and Jules de Goncourt.

The 1870s were difficult. Prussian soldiers occupied his house during the War of 1870, and in 1872, his mother died. After her death, he fell into financial straits. Flaubert suffered from venereal diseases most of his life. His health declined and he died at Croisset of a stroke in 1880 at the age of 58. He was buried in the family vault in the cemetery of Rouen. A monument to him by Henri Chapu was unveiled at the museum of Rouen in 1890.

In September 1849, Flaubert completed the first version onovel, which took five years to write, was serialized in the Revue de Paris in 1856. The government brought an action against the publisher and against the author on the charge of immorality, but both were acquitted. When Madame Bovary appeared in book form, it met with a warm reception.

In 1858, Flaubert traveled to Carthage to gather material for his next novel, Salammbô. The novel was completed in 1862 after four years of work.

Drawing on his childhood experiences, Flaubert next wrote L`Education sentimentale (Sentimental Education), an effort that took seven years. L`Education sentimentale, his last complete novel, was published in 1869.

He wrote an unsuccessful drama, Le Candidat, and published a reworked version of La Tentation de Saint-Antoine, portions of which had been published as early as 1857. He devoted much of his time to an ongoing project, Les Deux Cloportes (The Two Woodlice), which later became Bouvard et Pecuchet, breaking from the obsessive project only to write