He served as bishop of the Diocese of Providence in Rhode Island from 1934 to 1947 and as archbishop of the Archdiocese of Baltimore in Maryland from 1947 until his death.

[1] He received his early education at the parochial school of St. Mary's Church in New Britain, and began his studies for the priesthood at St. Thomas Seminary in Bloomfield, Connecticut.

[1] During the next 15 years, Keough served as the diocesan director of the Society for the Propagation of the Faith, as assistant chancellor of the diocese, and as chaplain of two institutions.

[3] During Keough's tenure in Providence, the Catholic population of the diocese increased from 325,000 to 425,000, and the number of clergy grew by fifty percent.

[4] He worked to ease tensions between the French- and English-speaking members of his congregation, and reduced the heavy financial debts burdening the diocese.

[2] In 1942, during World War II, Keough delivered the blessing at the launching of the SS William Coddington.

Like other Catholic bishops of the early Cold War era, Keough was a strong foe of Soviet communism.

At a commencement address at the University of Notre Dame in 1950, he warned that 2000 years of Christianity was "...crumbling before the juggernaut of communism.

[7] In 1956, Keough banned Catholics in the archdiocese from viewing the 1956 film Baby Doll, ostensibly because of its sexual themes.