Pope Francis named him to succeed
Juan Luis Cipriani Thorne as Archbishop of Lima on 25 January 2019. As Archbishop he is
ex officio Grand Chancellor of the Faculty of Civil and Canon Theology of Lima. When named archbishop, he was a lecturer in theology–a position he had held since 1987–and assessor of the Center for University Pastoral Assistance at the
Pontifical Catholic University of Peru. He also assisted in parish work at Church of San Francisco Solano. In addition to Spanish, he speaks Italian and French. At the press conference announcing his appointment, he received from his friend,
Luis Bambarén, Bishop Emeritus of Chimbote, the crozier that belonged to Cardinal Landázuri, who ordained him. But
Austen Ivereigh called it "an ecclesial earthquake". Without naming Cipriani, Cardinal
Pedro Barreto said Castillo's appointment "brings the Peruvian conference of bishops much closer to the reality of the church of which we all dream, a church that is poor and for the poor, a church that reaches out, a church that is closer to those who are suffering now."
John L. Allen Jr., citing the differences between Cipriani and Castillo on liberation theology and the Pontifical University, wrote that "it's still fairly unusual to see a cardinal's legacy disassembled in real time quite like this". Castillo's consecration and installation ceremony was held on 2 March 2019. He was consecrated by the
apostolic nuncio to Peru Archbishop
Nicola Girasoli, with Cardinals Cipriani and Barreto, Archbishop Héctor Miguel Cabrejos Vidarte and Bishop Luis Bambarén Gastelumendi serving as
co-consecrators. During the ceremony the liberation theologian,
Gustavo Gutiérrez, speaking as representative of the church of Lima, formally called upon the papal nuncio to ordain Mattasoglio as bishop. According to Edgar Beltrán writing in
the Pillar, among the Peruvian bishops, Castillo was a leading opponent of then bishop of
Chiclayo Robert Prevost, reportedly telling his colleagues that "a
yankee couldn't become a president of the bishops' conference." On 6 October 2024, Pope Francis announced that he planned to make Castillo a cardinal on 8 December, a date that was later changed to 7 December. On 7 December 2024, Pope Francis made him a cardinal, assigning him as Cardinal-Priest the title of
Santa Maria delle Grazie a Casal Boccone. He participated as a
cardinal elector in the
2025 papal conclave that elected
Pope Leo XIV. ==Selected writings==