Second Bishop of Boston, brother of Edward Dominic Fenwork. He studied and taught at Georgetown. In 1805 he entered the Sulpician Seminary in Baltimore, Maryland, but on the restoration of the Society of Jesus in the United States in 1806, he joined the Order. Ordained by Bishop Neale on 11 June 1808, he was sent to New York, where he became head of the New York Literary Institution, founded in 1809 as a college on the present site of the cathedral; it closed in 1814 on the recall of the Jesuits to Maryland. He served for a time as administrator of the New York diocese and under Bishop Connolly as vicar-general. From 1817-1818 he was president of Georgetown. Sent to Charleston in 1818, to arrange difficulties originating in the trustee system, he remained there two years after the arrival of Bishop England in 1820. He was again president of Georgetown, 1824-1825. Named to succeed Bishop Cheverus of Boston, he was consecrated in Baltimore on 1 November 1825. He established a seminary in his own home, and by 1827 had a school in the basement of the cathedral. In 1829 he founded one of the earliest Catholic papers in the United States, “The Jesuit, or the Catholic Sentinel.” His zeal resulted in the building within 20 years of 35 churches, of which eight were in Boston. He removed the Ursulines from an unsuitable location in Boston to Charlestown, early in his episcopacy; in 1834 the convent was destroyed at the hands of a fanatical mob. Their actions were condemned at a public meeting in Faneuil Hall, presided over by the mayor of Boston. In 1843, Bishop Fenwick established the Jesuits in charge of Holy Cross College at Worcester, replacing a former academy founded by Father James Fitton in 1838. At his death, the Catholics in Massachusetts numbered 53,000, an increase of 20,000 in 10 years.