Pietro da Cortona came to Rome about 1612 and soon entered the services of the Sacchetti family, in whose house he lived from 1623 onwards. His major pictorial work in their service was the decoration of the family villa at Castelfusano (1627-9). An introduction to the Barberini family through Marcello Sacchetti resulted in Cortona's first monumental commission, the decoration of the ceiling of the 'gran salone' of the Palazzo Barberini, Rome, with the 'Allegory of Divine Providence and Barberini Power', a work that he painted between 1631 and 1639 and which is generally considered the masterpiece of his early period. The ceiling is a triumph of illusionism and ample proof that by about 1630 he had assimilated a Venetian richness of colour which was to remain characteristic of his painting style.
Cortona subsequently became one of the central figures in the ambitious art projects of the Barberini pope, Urban VIII. Cortona's election as principe of the Accademia di San Luca for the years 1634 to 1637 is further indication of his professional success at the time.
In 1637 Cortona interrupted his work on the Barberini ceiling in order to travel north. Passing through Florence he commenced frescoes in the Palazzo Pitti, commissioned by the Grand Duke of Tuscany, and in turn interrupted these to complete the Barberini ceiling, but returned from 1641 to 1647 in order to finish the work. The Pitti decorations include frescoes of the 'Four Ages' in one room (the Sala della Stufa) and scenes relating to the planets Venus, Jupiter, Mars, Apollo and Saturn on the ceilings of five further rooms. The decorations of these planetary rooms inaugurated a new relationship in art between three-dimensional stuccowork and illusionistic paintings contained within heavy, stuccoed frames.
Of note among his later work in Rome are the frescoes for the apse, dome and pendentives of the Chiesa Nuova (1647-65), his most extensive ecclesiastical commission, as well as the 'Aeneas' series in the Gallery of the Palazzo Pamphilj (1651-4), commissioned by Innocent X. Stylistically these herald a departure away from the exuberant work of the 1630s towards a more sober idiom, in particular from the 1650s onwards. During the last decade of his life he was much hampered by gout and his production slowed.
As an architect Cortona ranks in importance with Bernini and Borromini, often managing large architectural and pictorial commissions simultaneously. Among his major achievements the church of SS Martina e Luca (1635-50), the modernisation of S. Maria della Pace (1656-7), the façade of S.Maria in Via Lata (1658-62) and the dome of SS Ambrogio e Carlo al Corso (begun 1668) are foremost.
The draughtsmanship of his early years (1620s) is indebted to the style prevalent in Florence around the turn of the century, as exemplified by the work of Ludovico Cardi, called Cigoli and Domenico Passignano. His later drawings, in particular the chalk figure studies, reveal a thorough study of Annibale Carracci's late graphic style.
Cortona was the head of a large studio which included Giovanni Francesco Romanelli, Giacinto Gimignani, Ciro Ferri and Lazzaro Baldi, who perpetuated his style. The activity of these 'Cortoneschi' was an important element in Roman painting in the second half of the seventeenth century. Together with Andrea Sacchi , who represents a taste for a more restrained and classical language, Cortona is considered the most important exponent of the Roman Baroque style in painting.