John Constable was born in East Bergholt, a village on the River Stour in Suffolk, to Golding and Ann (Watts) Constable. His father was a wealthy corn merchant, owner of Flatford Mill in East Bergholt and, later, Dedham Mill in Essex. Golding Constable also owned his own small ship, The Telegraph, which he moored at Mistley on the Stour estuary and used to transport corn to London. He was a cousin of the London tea merchant, Abram Newman. Although Constable was his parents' second son, his older brother was mentally handicapped and so John was expected to succeed his father in the business, and after a brief period at a boarding school in Lavenham, he was enrolled in a day school in Dedham. Constable worked in the corn business after leaving school, but his younger brother Abram eventually took over the running of the mills.
In his youth, Constable embarked on amateur sketching trips in the surrounding Suffolk and Essex countryside that was to become the subject of a large proportion of his art. These scenes, in his own words, "made me a painter, and I am grateful"; "the sound of water escaping from mill dams etc., willows, old rotten planks, slimy posts, and brickwork, I love such things." He was introduced to George Beaumont, a collector, who showed him his prized Hagar and the Angel by Claude Lorrain, which inspired Constable. Later, while visiting relatives in Middlesex, he was introduced to the professional artist John Thomas Smith, who advised him on painting but also urged him to remain in his father's business rather than take up art professionally.
In 1799, Constable persuaded his father to let him pursue art, and Golding even granted him a small allowance. Entering the Royal Academy Schools as a probationer, he attended life classes and anatomical dissections as well as studying and copying Old Masters. Among works that particularly inspired him during this period were paintings by Thomas Gainsborough, Claude Lorrain, Peter Paul Rubens, Annibale Carracci and Jacob van Ruisdael. He also read widely among poetry and sermons, and later proved a notably articulate artist. By 1803, he was exhibiting paintings at the Royal Academy.
His early style has many of the qualities associated with his mature work, including a freshness of light, colour and touch, and reveals the compositional influence of the Old Masters he had studied, notably of Claude Lorrain. Constable's usual subjects, scenes of ordinary daily life, were unfashionable in an age that looked for more romantic visions of wild landscapes and ruins. He did, however, make occasional trips further afield. For example, in 1803 he spent almost a month aboard the East Indiaman ship Coutts as it visited south-east coastal ports, and in 1806 he undertook a two-month tour of the Lake District. But he told his friend and biographer Charles Leslie that the solitude of the mountains oppressed his spirits.