[4] His father was a small shipping merchant[5] who belonged to a family that bore the prestigious patrician name of Tiepolo without claiming any noble descent.

Some of the children acquired noble godparents, and Giambattista was originally named after his godfather, a Venetian nobleman called Giovanni Battista Dorià.

He was, though, at least equally strongly influenced by his study of the works of other contemporary artists such as Sebastiano Ricci, Giovanni Battista Piazzetta and Federico Bencovich,[5] as well those of his Venetian predecessors, especially Tintoretto and Veronese.

[6] A biography of his teacher, published in 1732, says that Tiepolo "departed from [Lazzarini's] studied manner of painting, and, all spirit and fire, embraced a quick and resolute style".

[7] At about the same time he became painter to the Doge, Giovanni II Cornaro, and oversaw the hanging of pictures at his palace, as well as painting many works himself, of which only two portraits have been identified.

Tiepolo depicted the Triumph of Aurora on the ceiling, and the Myth of Phaethon on the walls, creating the kind of fluid spatial illusion which was to become a recurring theme in his work.

[10] In 1722 he was one of twelve artists commissioned to contribute a painting on canvas of one of the apostles as part of a decorative scheme for the nave of San Stae in Venice.

Despite their elevated subject matter, they are bright in colour, and light-hearted in mood: Michael Levey describes the paintings at the palace as "a shimmering set of tableaux, full of wit and elegance".

He painted canvases for churches such as that of Verolanuova (1735–1740), for the Scuola Grande dei Carmini (1740–1747), in Cannaregio, a ceiling for the Palazzi Archinto and Palazzo Dugnani in Milan (1731), the Colleoni Chapel in Bergamo (1732–1733), a ceiling for the Gesuati (Santa Maria del Rosario) in Venice of St. Dominic Instituting the Rosary (1737–1739), Palazzo Clerici, Milan (1740), decorations for Villa Cordellina Molin, a ceiling for the Chiesa degli Scalzi (1743–1744); now destroyed (reconstitution :[14]), Villa Cordellina Molin, Montecchio Maggiore (1743–1744) and for the ballroom of the Palazzo Labia in Venice (now a television studio), showing the Story of Cleopatra (1745–1750).

[15] The 23 Scherzi were etched over more than ten years and privately circulated, only being commercially published after Tiepolo's death, with numbers and titles added by his son, Giandomenico.

In 1761, King Charles III of Spain commissioned Tiepolo to create a ceiling fresco to decorate the throne room of the Royal Palace of Madrid.

was sufficiently respected to be painter to Doge Giovanni II Cornaro, in charge of the decoration of Palazzo Mocenigo in the sestiere of San Polo, Venice.