Joseph Mallord William Turner was born on 23 April 1775 and baptised on 14 May. He was born in Maiden Lane, Covent Garden, in London, England. His father, William Turner (1745–21 September 1829), was a barber and wig maker. His mother, Mary Marshall, came from a family of butchers. A younger sister, Mary Ann, was born in September 1778 but died in August 1783.
Turner's mother showed signs of mental disturbance from 1785 and was admitted to St Luke's Hospital for Lunatics in Old Street in 1799 and was moved in 1800 to Bethlem Hospital, a mental asylum, where she died in 1804. Turner was sent to his maternal uncle, Joseph Mallord William Marshall, in Brentford, then a small town on the banks of the River Thames west of London. The earliest known artistic exercise by Turner is from this period—a series of simple colourings of engraved plates from Henry Boswell's Picturesque View of the Antiquities of England and Wales.
Around 1786, Turner was sent to Margate on the north-east Kent coast. There he produced a series of drawings of the town and surrounding area that foreshadowed his later work. By this time, Turner's drawings were being exhibited in his father's shop window and sold for a few shillings. His father boasted to the artist Thomas Stothard that: "My son, sir, is going to be a painter". In 1789, Turner again stayed with his uncle who had retired to Sunningwell in Berkshire (now part of Oxfordshire). A whole sketchbook of work from this time in Berkshire survives as well as a watercolour of Oxford. The use of pencil sketches on location, as the foundation for later finished paintings, formed the basis of Turner's essential working style for his whole career.
Many early sketches by Turner were architectural studies or exercises in perspective, and it is known that, as a young man, he worked for several architects including Thomas Hardwick, James Wyatt and Joseph Bonomi the Elder. By the end of 1789, he had also begun to study under the topographical draughtsman Thomas Malton, specialised in London views. Turner learned from him the basic tricks of the trade, copying and colouring outline prints of British castles and abbeys. He would later call Malton "My real master". Topography was a thriving industry by which a young artist could pay for his studies.
Turner entered the Royal Academy of Art in 1789, aged 14, and was accepted into the academy a year later by Sir Joshua Reynolds. Turner showed an early interest in architecture, but was advised by Thomas Hardwick to focus on painting. His first watercolour, A View of the Archbishop's Palace, Lambeth was accepted for the Royal Academy summer exhibition of 1790 when Turner was 15.
As an academy probationer, Turner was taught drawing from plaster casts of antique sculptures. From July 1790 to October 1793, his name appears in the registry of the academy over a hundred times. In June 1792, he was admitted to the life class to learn to draw the human body from nude models. Turner exhibited watercolours each year at the academy while painting in the winter and travelling in the summer widely throughout Britain, particularly to Wales, where he produced a wide range of sketches for working up into studies and watercolours. These particularly focused on architectural work, which used his skills as a draughtsman. In 1793, he showed the watercolour titled The Rising Squall – Hot Wells from St Vincent's Rock Bristol (now lost), which foreshadowed his later climatic effects. Cunningham in his obituary of Turner wrote that it was: "recognised by the wiser few as a noble attempt at lifting landscape art out of the tame insipidities...[and] evinced for the first time that mastery of effect for which he is now justly celebrated".
In 1796, Turner exhibited Fishermen at Sea, his first oil painting for the academy, of a nocturnal moonlit scene of the Needles off the Isle of Wight, an image of boats in peril. Wilton said that the image: "Is a summary of all that had been said about the sea by the artists of the 18th century". and shows strong influence by artists such as Claude Joseph Vernet, Philip James de Loutherbourg, Peter Monamy and Francis Swaine, who was admired for his moonlight marine paintings. This particular painting cannot be said to show any influence of Willem van de Velde the Younger, as not a single nocturnal scene is known by that painter. Some later work, however, was created to rival or complement the manner of the Dutch artist. The image was praised by contemporary critics and founded Turner's reputation, as both an oil painter and a painter of maritime scenes