Giovanni Antonio Canal was born in Venice as the son of the painter Bernardo Canal, hence his mononym Canaletto ("little Canal"), and Artemisia Barbieri. Canaletto served his apprenticeship with his father and his brother. He began in his father's occupation, that of a theatrical scene painter. Canaletto was inspired by the Roman vedutista Giovanni Paolo Pannini, and started painting the daily life of the city and its people.
After returning from Rome in 1719, he began painting in his topographical style. His first known signed and dated work is Architectural Capriccio (1723, Milan, in a private collection). Studying with the older Luca Carlevarijs, a well-regarded painter of urban cityscapes, he rapidly became his master's equal.
In 1725, the painter Alessandro Marchesini, who was also the buyer for the Lucchese art collector Stefano Conti, had inquired about buying two more 'views of Venice', when the agent urged him to consider instead the work of "Antonio Canale... it is like Carlevaris, but you can see the sun shining in it."
Much of Canaletto's early artwork was painted "from nature", differing from the then customary practice of completing paintings in the studio. Some of his later works do revert to this custom, as suggested by the tendency for distant figures to be painted as blobs of colour – an effect possibly produced by using a camera obscura, which blurs farther-away objects – although research by art historians working for the Royal Collection in the United Kingdom has shown Canaletto almost never used a camera obscura.
However, his paintings are always notable for their accuracy: he recorded the seasonal submerging of Venice in water and ice.
Canaletto's early works remain his most coveted and, according to many authorities, his best. One of his early pieces is The Stonemason's Yard (c. 1725, the National Gallery, London) which depicts a humble working area of the city. It is regarded one of his finest works and was presented by Sir George Beaumont in 1823 and 1828.
Later Canaletto painted grand scenes of the canals of Venice and the Doge's Palace. His large-scale landscapes portrayed the city's pageantry and waning traditions, making innovative use of atmospheric effects and strong local colours. For these qualities, his works may be said to have anticipated Impressionism.
His graphic print S. A. Giustina in Prà della Vale was found in the 2012 Munich Art Hoard
Many of his pictures were sold to Englishmen on their Grand Tour, first through the agency of Owen Swiny and later the banker Joseph Smith, appointed British Consul in Venice in 1744. It was Swiny in the late 1720s who encouraged the artist to paint small topographical views of Venice with a commercial appeal for tourists and foreign visitors to the city. Sometime before 1728, Canaletto began his association with Joseph Smith, an English businessman and collector living in Venice, who later became the artist's principal agent and patron. Smith eventually acquired nearly fifty paintings, one hundred fifty drawings, and fifteen rare etchings from Canaletto, the largest and finest single group of the artist's works, that he sold to King George III in 1763.
In the 1740s Canaletto's market was disrupted when the War of the Austrian Succession led to a reduction in the number of British visitors to Venice. Smith also arranged for the publication of a series of etchings of "capricci" (or architectural phantasies) (capriccio Italian for fancy) in his vedute ideale, but the returns were not high enough, and in 1746 Canaletto moved to London, to be closer to his market.
He remained in England until 1755, producing views of London (including several of the new Westminster Bridge, which was completed during his stay) and of his patrons' castles and houses. His 1754 painting of Old Walton Bridge includes an image of Canaletto himself.
He was often expected to paint England in the fashion with which he had painted his native city. Canaletto's painting began to suffer from repetitiveness, losing its fluidity, and becoming mechanical to the point that the English art critic George Vertue suggested that the man painting under the name 'Canaletto' was an impostor. Historian Michael Levey described his work from this period as "inhibited".
The artist was compelled to give public painting demonstrations in order to refute this claim; however, his reputation never fully recovered in his lifetime.
After his return to Venice, Canaletto was elected to the Venetian Academy in 1763 and appointed prior of the Collegio dei Pittori. He continued to paint until his death in 1768. In his later years he often worked from old sketches, but he sometimes produced surprising new compositions. He was willing to make subtle alterations to topography for artistic effect.