I whakaritea a O'Malley hei episekopo o te Diocese o Saint Thomas i te Mei 30, 1984, na Pope John Paul II. I riro i a ia tana whakatapunga episekopo i te Akuhata 2 e whai ake nei na Bishop Edward John Harper, me te Archbishop James Hickey me te Pihopa Eugene Marino e mahi ana hei kaiwhakaatu.
Ko te Pihopa Nui