Rubuta ci gaba don wannan sakin layi - A ranar 27 ga Nuwamba, 1911, O'Connell ya zama Babban Bishop na farko na Boston don zama Cardinal, kuma an ba shi taken Cardinal-Priest na S. Clemente. Ya makara zuwa taron papal guda biyu a jere, a shekara ta 1914 da 1922, saboda dole ne ya ƙetare Tekun Atlantika a cikin jinkirin sufuri na ranar. Ya yi gunaguni ga Paparoma Pius XI, wanda ya ba da amsa ya tsawaita lokacin da ke tsakanin mutuwar Paparoma da farkon taron. O'Connell a karshe ya sami damar shiga cikin taron 1939 na gaba
, ko da yake a wannan lokacin jirgin sama yana samuwa.