He was a captain in the Peruvian campaign to Peru, fought in the Battle of Cerro de Pasco and was decorated for the defense of the city of Lima.
After this last battle, Paz sent Castillo to his home province of Mendoza to overthrow the government of Juan Rege Corvalán, a Federalist ally of Facundo Quiroga.
In early April 1830 he entered Mendoza, where he held a "town meeting" consisting exclusively of Unitarians that elected Tomás Godoy Cruz as acting governor.
He left hurriedly to deal with the threat, but his troops were destroyed by Quiroga in the Battle of Rodeo de Chacón on 28 March 1831.
He dedicated himself to the production of coffee, sugar and pepper in Santa Cruz de la Sierra, but a fire destroyed his property, causing him severe depression.