Born in Mignano Monte Lungo, near Naples, Mancini emigrated to Canada with his family, arriving at Pier 21 on December 1, 1948, and was raised in Montreal.
Archbishop Mancini received a Bachelor of Arts from Resurrection College at the University of Waterloo, a Licentiate in Theology from Université de Montréal, a Master of Arts in religious studies from McGill University, studies in ecumenical theology at the University of Geneva and his Doctor of Philosophy in pastoral theology at Université de Montréal.
Archbishop Mancini was ordained a priest in the Archdiocese of Montreal on May 23, 1970. On February 18, 1999, he was appointed an Auxiliary Bishop of Montreal by Cardinal Jean-Claude Turcotte.
On October 18, 2007, he was appointed to the Archdiocese of Halifax, succeeding Archbishop Terrence Thomas Prendergast as the ordinary. At the same time, Mancini was appointed Apostolic Administrator of the Diocese of Yarmouth after Bishop James Matthew Wingle was transferred to the Diocese of Saint Catharines. He was installed to these positions on November 29, 2007.
On September 26, 2009, Archbishop Mancini also became the Apostolic Administrator of the Diocese of Antigonish following the resignation of Bishop Raymond Lahey. This lasted until November 21, 2009, when the Holy See appointed Bishop Brian Dunn as ordinary of that diocese.
On December 8, 2011, Pope Benedict XVI merged the Diocese of Yarmouth with the Archdiocese of Halifax to form the Archdiocese of Halifax-Yarmouth. Archbishop Mancini became the first leader of the newly formed Archdiocese.
On November 25, 2020, a report was released detailing how a Catholic church-commissioned investigation led by former Quebec Superior Court justice Pepita Capriolo found that Mancini was among the former Archdiocese of Montreal officials who took no action against Father Brian Boucher after receiving reports Boucher sexually abused boys.[1] Boucher pled guilty in January 2019 to sex abuse charges and received an eight-year prison sentence.[1]
Archbishop Mancini retired on his 75th birthday, November 27, 2020. Mancini was Grand Prior of the Canada-Atlantic Lieutenancy of the Equestrian Order of the Holy Sepulchre of Jerusalem until his retirement.
