Pedzisa mutsara unotevera: Musi waNovember 27, 1911, O'Connell akava Bhishopi Mukuru wokutanga weBoston kuti ave Kadhinari, uye akapiwa zita rokuti Cardinal-Priest of S. Clemente. Akasvika kunonoka kumisangano miviri yapapa yakatevedzana, muna 1914 uye
1922, nemhaka yokufanira kuyambuka Atlantic Ocean mukufambisa kunononoka kwezuva racho. Akapikisa kuna Papa Pius XI, uyo akapindura nokuwedzera nguva iri pakati porufu rwaPapa nokuvamba kweconclave. O'Connell pakupedzisira akakwanisa kupinda musangano wakazotevera wa1939, kunyange zvazvo panguva iyoyo kufamba nendege kwakanga kwava kuwanika.