Pompeo Girolamo Batoni was born in Lucca, the son of a goldsmith.
He established himself in Rome in 1727 or 1728 to study the ancien sculpture. A pupil of Sebastiano Conca, he was however described as mainly a self-taught. His first works being mainly copies of works by Raphael and Annibale Carracci. In the early 1740s, however, he started to receive more prestige commissions, including the famous Fall of Simon Magus for the St. Peter's Basilica (now in Santa Maria degli Angeli). The Ecstasis of St. Catherine of Siena, now in the National Museum of Lucca, is from 1743.
Batoni became the most fashionable painter in the city, particularly after his most serious rival - Anton Raphael Mengs - departed for Spain in 1761. Batoni befriended Winckelmann and, like him, preferred Raphael and Poussin to the Venetian artists then in vogue.
His studio was frequented by foreigners, especially Britons, who would commission standing portraits in the milieu of antiquities, ruins, and objets d'art. Such "Grand Tourist" portraits by Batoni came to proliferate in the British private collections, thus ensuring the genre's popularity in the United Kingdom, where Sir Joshua Reynolds would become its leading practitioner.
In 1769 the double portrait of Joseph II and Leopold II won an Austrian nobility for Batoni. He also portrayed Pope Pius VI. According to a legend, he bequeathed his palette and brushes to Jacques-Louis David.
He died in Rome in 1787.