David Brum was born in Fresno, California, on November 16, 1954, to Orville and Marjory Brum, the eldest son in a Roman Catholic family. He was raised in Riverdale, a Portuguese-American area, and graduated high school in 1973. He enrolled in St Patrick's College Seminary, Mountain View, where he discovered the history of Orthodoxy and attended services at St Nicholas Church, Saratoga. He began reading the Church Fathers in the 1970s and tried to integrate his private study into his regular study. He graduated with a Bachelor of Arts in Humanities (specialising in hisotry, philosophy and English literature) before entering St Patrick's Seminary in Menlo Park, graduating with a Masters of Divinity in 1981 and being ordained a Roman Catholic priest that same year. He served in a variety of capacities, including in the Portuguese-American community (and editor of the Portuguese-language page of the diocesan newspaper) and as diocesan Director of Vocations.
He was asked by his bishop to continue further studies in 1992 and, in 1995, received a JCL (degree in canon law) from the Catholic University of America, Washington DC. During this time, his relationship with Orthodoxy continued with his research, and his study of canon law brought him closer to Orthodoxy. He nevertheless returned to his diocese and was assigned to the Diocesan Tribunal and a small, rural, mission parish.
It was ultimately his study of canon law that brought him to petition to be received into the Orthodox Church in America, and he was received by Vesting by Bp Tikhon of San Francisco and the West at the Monastery of St John of Shanghai & San Francisco. He served at St Nicholas Church, Saratoga, until he was assigned to St Paul the Apostle Church in Las Vegas. He was transferred to the Diocese of New York and New Jersey in August 1998 and assigned rector of St Gregory Palamas Mission, Flemington, New Jersey. He was appointed Secretary to Metropolitan Theodosius (Lazor) in 2000, continuing his service under Metropolitan Herman (Swaiko). He also served on several Church committees and commissions, including those utilising his knowledge of canon law.
In December 2005, he asked to return to parish ministry and, in July 2006, he was transferred to the Diocese of the West and appointed Rector of Sts Peter and Paul Church, Phoenix. He was elected a member of the Diocesan Council in October 2006.
On April 7, 2014, he was tonsured a monastic at the Monastery of St John of Shanghai, receiving the name Daniel.
On October 21, 2014, he was canonically elected Bishop of Santa Rosa, to serve as Auxiliary Bishop to Abp Benjamin of San Francisco in the Diocese of the West. He was elevated to Archimandrite on October 23, 2014.