Proust was born in Auteuil (the southern sector of Paris's then-rustic 16th arrondissement) at the home of his great-uncle, two months after the Treaty of Frankfurt formally ended the Franco-Prussian War. His birth took place during the violence that surrounded the suppression of the Paris Commune, and his childhood corresponds with the consolidation of the French Third Republic. Much of In Search of Lost Time concerns the vast changes, most particularly the decline of the aristocracy and the rise of the middle classes, that occurred in France during the Third Republic and the fin de siècle.

Proust's father, Achille Adrien Proust, was a prominent pathologist and epidemiologist, responsible for studying and attempting to remedy the causes and movements of cholera through Europe and Asia; he was the author of many articles and books on medicine and hygiene. Proust's mother, Jeanne Clémence Weil, was the daughter of a well-off and cultured Jewish family. She was a literate and well-read woman. Her letters demonstrate a well-developed sense of humour, and her command of English was sufficient for her to provide the necessary impetus to her son's later attempts to translate John Ruskin.^[1]

By the age of nine, Proust had his first serious asthma attack, and thereafter he was considered by himself, his family and his friends as a sickly child. Proust spent long holidays in the village of Illiers. This village, combined with aspects of the time he spent at his great-uncle's house in Auteuil became the model for the fictional town of Combray, where some of the most important scenes of In Search of Lost Time take place. (Illiers was renamed Illiers-Combray on the occasion of the Proust centenary celebrations).

Despite his poor health, Proust served a year (1889–90) as an enlisted man in the French army, stationed at Coligny Caserne in Orléans, an experience that provided a lengthy episode in The Guermantes' Way, part three of his novel. As a young man, Proust was a dilettante and a social climber, whose aspirations as a writer were hampered by his lack of application. His reputation from this period, as a snob and an amateur, contributed to his later troubles with getting Swann's Way, the first part of his large-scale novel, published in 1913.