Ordained to the priesthood on Dec. 24, 2003, Bishop Peter Dai Bui has been a priest of the Diocese of Phoenix for over 18 years. Announced by Pope Leo XIV on Dec. 19, 2025, Bishop Bui became the second auxiliary bishop in the 56-year history of the diocese when he was ordained on Feb. 17, 2026. He was ordained by Bishop John Dolan, and his co-consecrators were Bishop Emeritus Thomas Olmsted and Auxiliary Bishop Eduardo Nevares. Cardinal Christophe Pierre, Apostolic Nuncio to the United States, was also present. Bishop Bui assists Bishop Dolan as auxiliary bishop while continuing his role as Vicar for Clergy. The move came to support one of the fastest growing Catholic dioceses in the United States with a population of over 2 million Catholics.
Bishop Bui joined Auxiliary Bishop Nevares, who was ordained as the first auxiliary bishop for the Diocese of Phoenix on July 19, 2010. Appointed by a pope, an auxiliary bishop assists the bishop, and a diocese can have more than one.
Fluent in Spanish, German, Italian, English and Vietnamese, Bishop Bui brings a diverse background to the diocese, including serving six years at the Vatican (2011-2016). While in Rome, Bishop Bui was an official of the Pontifical Council Cor Unum, which leads charitable, humanitarian and disaster-relief efforts for the Church. It was in this role that he received the title of “Monsignor” in 2014 from Pope Francis.
Bishop Bui has served in various parish roles in the Diocese of Phoenix, including at Our Lady of Guadalupe Parish in Queen Creek (2007-2008), Christ the King Parish in Mesa (2008-2010), Resurrection Parish in Tempe (2010-2011) and Holy Spirit Parish in Tempe (2017-2022). He was appointed Vicar for Clergy for the diocese in July of 2022, a role he continues as an auxiliary bishop.
Prior to joining the Diocese of Phoenix in 2007, Bishop Bui was a missionary priest with the Legionaries of Christ, serving in places like Venezuela and Colombia. He was the chaplain at a high school in Caracas, Venezuela, organizing mission trips to the Amazon jungle to distribute food and offer the sacraments in remote areas.
Bishop Bui studied philosophy and theology at the Pontifical Athenaeum Regina Apostolorum in Rome. Born in Phu Quoc Island, Vietnam, he fled religious and political oppression in native country as a five-year-old in 1977, with his parents, nine siblings and others aboard his dad’s 30-foot fishing boat.
The Bui family’s heroic journey in 1977 was captured by an Associated Press photographer, Eddie Adams, and part of his book titled Vietnam. Adams’ images, including the famous shot of the Bui family and others crowded on the deck of the boat that he titled “Boat of No Smiles,” helped pave the way for some 200,000 Vietnamese immigrants to be admitted to the United States.
The family eventually settled in New Orleans, where his mother and several siblings still reside.
Birthday: Jan. 11, 1970
Ordination to priesthood: Dec. 24, 2003
Ordained Auxiliary Bishop of Phoenix: Feb. 17, 2026