In his youth, Tintoretto was also known as Jacopo Robusti as his Father had defended the gates of Padua in a way that others called robust, against the imperial troops during the War of the League of Cambrai (1509–1516). His real name "Comin" was discovered by Miguel Falomir of the Museo del Prado, Madrid, and was made public on the occasion of the retrospective of Tintoretto at the Prado in 2007. Comin translates to the spice cumin in the local language.

Tintoretto was born in Venice in 1518, as the eldest of 21 children. His Father, Giovanni, was a dyer, or tintore; hence the son got the nickname of Tintoretto, little dyer, or dyer's boy. The family was believed to have originated from Brescia, in Lombardy, then part of the Republic of Venice. Older studies gave the Tuscan town of Lucca as the origin of the family.

In childhood Jacopo, a born Painter, began daubing on the dyer's walls; his Father, noticing his bent, took him to the studio of Titian to see how far he could be trained as an Artist. This was supposedly around 1533, when Titian was (according to the ordinary accounts) over 40 years of age. Tintoretto had only been ten days in the studio when Titian sent him home for good, because the great master observed some very spirited drawings, which he learned to be the production of Tintoretto; it is inferred that he became at once jealous of so promising a student. This, however, is mere conjecture; and perhaps it may be fairer to suppose that the drawings exhibited so much independence of manner that Titian judged that young Jacopo, although he might become a Painter, would never be properly a pupil.

Towards 1546 Tintoretto painted for the church of the Madonna dell'Orto three of his leading works: the Worship of the Golden Calf, the Presentation of the Virgin in the Temple, and the Last Judgment. He took the commission for two of the paintings, the Worship of the Golden Calf and the Last Judgment, on a cost only basis in order to make himself better known. He settled down in a house hard by the church. It is a Gothic building, looking over the Fondamenta de Mori, which is still standing. In 1548 he was commissioned for four pictures for the Scuola di S. Marco: the Finding of the body of St Mark, the St Mark's Body Brought to Venice, a St Mark Rescuing a Saracen from Shipwreck and the Miracle of the Slave. (these three are in Gallerie dell'Accademia Venice). The latter represents the legend of a Christian slave or captive who was to be tortured as a punishment for some acts of devotion to the evangelist, but was saved by the miraculous intervention of the latter, who shattered the bone-breaking and blinding implements which were about to be applied.

In 1550, Tintoretto married Faustina de Vescovi (Episcopi?), daughter of a Venetian nobleman who was the guardian grande of the Scuola Grande di San Marco. She appears to have been a careful housekeeper, and able to mollify her husband. Faustina bore him several children, likely two sons and five daughters. Tintoretto had had a bastard daughter by Marietta Robusti, herself a portrait Painter, before his marriage to Faustina.

It was probably in 1560, the year in which he began working in the Scuola di S. Rocco, that Tintoretto commenced his numerous paintings in the Doge's Palace; he then executed there a portrait of the Doge, Girolamo Priuli. Other works (destroyed by a fire in the palace in 1577) succeeded—the Excommunication of Frederick Barbarossa by Pope Alexander III and the Victory of Lepanto.

In 1565 he resumed work at the scuola, painting the Crucifixion, for which a sum of 250 ducats was paid. In 1576 he presented gratis another centre-piece—that for the ceiling of the great hall, representing the Plague of Serpents; and in the following year he completed this ceiling with pictures of the Paschal Feast and Moses striking the Rock accepting whatever pittance the confraternity chose to pay.

Tintoretto next launched out into the painting of the entire scuola and of the adjacent church of San Rocco. He offered in November 1577 to execute the works at the rate of 100 ducats per annum, three pictures being due in each year. This proposal was accepted and was punctually fulfilled, the painter's death alone preventing the execution of some of the ceiling-subjects. The whole sum paid for the scuola throughout was 2447 ducats. Disregarding some minor performances, the scuola and church contain fifty-two memorable paintings, which may be described as vast suggestive sketches, with the mastery, but not the deliberate precision, of finished pictures, and adapted for being looked at in a dusky half-light. Adam and Eve, the Visitation, the Adoration of the Magi, the Massacre of the Innocents, the Agony in the Garden, Christ before Pilate, Christ carrying His Cross, and (this alone having been marred by restoration) the Assumption of the Virgin are leading examples in the scuola; in the church, Christ curing the Paralytic.

While the commission for this huge work was yet pending and unassigned Tintoretto was wont to tell the senators that he had prayed to God that he might be commissioned for it, so that paradise itself might perchance be his recompense after death. Upon eventually receiving the commission in 1588, he set up his canvas in the Scuola della Misericordia and worked indefatigably at the task, making many alterations and doing various heads and costumes direct from life.

In 1592 he became a member of the Scuola dei Mercanti.

In 1594, he was seized with severe stomach pains, complicated with fever, that prevented him from sleeping and almost from eating for a fortnight. He died on May 31, 1594. He was buried in the church of the Madonna dell'Orto by the side of his favorite daughter Marietta, who had died in 1590 at the age of thirty. Tradition suggests that as she lay in her final repose, her heart-stricken Father had painted her final portrait.

Marietta had herself been a portrait-painter of considerable skill, as well as a musician, vocalist and instrumentalist, but few of her works are now traceable. It is said that up to the age of fifteen she used to accompany and assist her Father at his work, dressed as a boy. Eventually, she married a jeweler, Mario Augusta. In 1866 the grave of the Vescovi—his wife's family—and Tintoretto was opened, and the remains of nine members of the joint families were found in it. The grave was then moved to a new location, to the right of the choir.

In 2013, the Victoria and Albert Museum announced that the painting The Embarkation of St Helena in the Holy Land had been painted by Tintoretto (and not by his contemporary Andrea Schiavone, as previously thought) as part of a series of three paintings depicting the legend of St Helena And The Holy Cross.

An agreement is extant showing a plan to finish two historical paintings—each containing twenty figures, seven being portraits—in a two-month period of time. The number of his portraits is enormous; their merit is uneven, but the really fine ones cannot be surpassed. Sebastiano del Piombo remarked that Tintoretto could paint in two days as much as himself in two years; Annibale Carracci that Tintoretto was in many of his pictures equal to Titian, in others inferior to Tintoretto. This was the general opinion of the Venetians, who said that he had three pencils—one of gold, the second of silver and the third of iron.