Benavides was notified of his appointment as Captain General of Chile in May 1780, and immediately started the long trip overland.
He had to stop and winter in the city of Mendoza but finally managed to arrive in Santiago on December 11, assuming his position the next day.
On April 13, a strong earthquake affected Santiago and on June 16, the Mapocho River, after nine days of uninterrupted rain, flooded the city.
He paid much attention to the construction of the Maipo channel, and the reconstruction of Santiago after the floods of 1783, including moving La Moneda from its original location by the river to the current one.
On March 27, 1787, he officially appointed Tomás Álvarez de Acevedo as interim governor and retired to Cauquenes to try to restore his health.