Born at Haro, he took the Augustinian habit at the Convento de Nuestra Señora del Risco in the Diocese of Ávila.
He studied at the University of Salamanca and was a disciple of Enrique Flórez, who took him along with him on his voyages of historical research.
On Flórez's death Risco took over the unfinished Church history of Spain, España Sagrada.
He published thirteen volumes of the España Sagrada, from thirty to forty-two, inclusive.
In 1800 ill health forced him to resign from the project and he ended his days at the Monasterio de San Felipe el Real in Madrid.