The building was began by Pietro Aldobrandini who gave the direction of works to Matteo Bartonili da Città di Castello (1580-1586). According to the sources Giacomo della Porta and Carlo Maderno worked in the site. In 1659 the building, not yet finished, was bought by Pope Alexander VII for his family, after whom it is named. The building was completed in the Baroque era. 

Since 1917, when it was acquired by the State, the Palazzo Chigi has been associated with politics. Since the 1970s, after a complete restoration (1959-61), the palace is the seat of the Presidency of the Council of Ministers.

Outside, the building follows the severe concepts of the Counter-Reformation. On the main facade, on Via del Corso, the windows of the first floor have round and triangular tympanums. 

The face to Piazza Colonna is larger and has a rich portal (1739). Inside are worth seeing the cortile della Greca, with a fountain decorated with the coat of arms of the Chigi and Della Rovere families (1749) and the flight of steps leading to the first floor, where is the Salone del Consiglio dei Ministri. In the ceiling of the Salone d'oro, a neoclassical hall designed by Giovanni Stern (1765-1767), is the Sleeping Endimion by Baciccia.