Brummell's grandfather was a shopkeeper in the parish of St. James, London, who let lodgings to the aristocracy; his father was private secretary to Lord North from 1770 to 1782 and subsequently high sheriff of Berkshire. From his early years Brummell paid great attention to his dress. At Eton, where he was sent to school in 1790 and was extremely popular, he was known as “Buck Brummell,” and at Oxford, where he spent a brief period as an undergraduate at Oriel College, he preserved this reputation for fashion and added to it that of a wit. He returned to London, where the Prince of Wales, to whom he had been presented at Eton, gave him a commission in his own regiment (1794). Brummell soon became intimate with his patron, and, in 1798, having then reached the rank of captain, he left the service.

In 1799 he succeeded to a fortune of about £30,000 (a bequest from his father, who had died in 1794). Setting up a bachelor establishment in Mayfair, he became, as a result of the Prince of Wales's friendship and his own good taste in dress, the recognized arbiter of fashion and a frequenter of all society's gatherings. For a time his influence was unchallenged, but eventually gambling and extravagance exhausted his fortune, while his tongue proved too sharp for his royal patron. They quarreled in 1812, and, although Brummell did not immediately lose his place in society, his debts increased so much that on May 16, 1816, he fled to Calais to avoid his creditors. There he struggled on for 14 years, always hopelessly in debt. From 1830 to 1832 he was British consul at Caen. In 1835 he was imprisoned for debt, but his friends once more came to the rescue and provided him with a small income. He soon lost all his interest in dress; his personal appearance was slovenly and dirty, and he began to live fantasies in the past. In 1837, after two attacks of paralysis, shelter was found for him in the charitable asylum of Bon Sauveur, Caen, where he spent his final years.