The first Catholic church was established on Guam on June 15, 1668 by Spanish-Filipino missionaries Diego Luis de San Vitores and Pedro Calungsod.

[3] On October 31, 2016, after months of an Apostolic Administration, Pope Francis appointed Michael J. Byrnes of the Archdiocese of Detroit to become Coadjutor Archbishop of Agaña with special faculties.

However, the verdict of the First Instance canonical penal trial was upheld by the Apostolic Tribunal of the Congregation for the Doctrine of the Faith (CDF) on February 7, 2019.

[6] On January 15, 2019 it was announced that the Archdiocese filed for Chapter 11 bankruptcy due to the financial burden created by the overwhelming amount of sex abuse lawsuits.

[10][11] In August 2019, it was revealed that 223 people had filed lawsuits against 35 clergymen, teachers and Boy Scout leaders tied to the Catholic Church whom they accused of sexually abusing them while serving with the Archdiocese of Agaña.

[21] The Boy Scouts of America, the Capuchin Franciscans, and some of the people named as defendants in the lawsuits had already started making settlements with clergy sex abuse survivors since 2018.

[20][22] However, the October 2019 negotiations, which were mediated by U.S. Bankruptcy Judge for the District of Hawaii Robert J. Faris, were cut short after the survivors rejected the settlement offers and continued to pursue their lawsuits.

[24] On March 23, 2021, US Federal District Judge Frances Tydingco-Gatewood denied Apuron's motion to temporarily halt proceedings in Guam's clergy sex abuse cases.

During this time, masses were held virtually, with church-goers watching church broadcasts through radio stations and social media platforms, such as Facebook Live.

[27] On March 29, 2023, Archbishop Michael J. Byrnes resigned due to a "life-changing illness", leaving Vicar General Father Romeo Convocar to lead the church in his absence.