Juan Pardo de Tavera was born in Toro, Zamora on 16 May 1472, the son of Ares Pardo and Guiomar Tavera.[2] On his mother's side, he was the nephew of Diego Deza, who would serve as his patron and mentor.[2] He studied at the University of Salamanca, receiving a bachelor's degree in 1500 and a Licentiate of Canon Law in 1505.[2] He became the rector of the university in 1505.[2]
He became president of the Royal Council in 1524 and held that office for the next fifteen years.[2] Under his rule the Royal Council was reorganized and renamed Council of Castile and the Council of the Indies was split from the Council of Castile. He presided over the Cortes Generales held in Toledo (1525), Valladolid (1527), Madrid (1528), Valladolid (1537), and Toledo (1538).[2]
Following the death of Isabella of Portugal on 1 May 1539, Charles V appointed Juan Pardo de Tavera regent of Castile in his absence, a post he would hold until 1541.[2] At the same time, he was appointed Grand Inquisitor of Spain on 10 June 1539 and he began his duties as Grand Inquisitor on 7 December 1539.[2]