Buuxi weedha soo socota: Bishii Nofeembar 27, 1911, O'Connell wuxuu noqday Boston Archbishop-kii ugu horreeyay ee noqda Cardinal, waxaana la siiyay cinwaanka Cardinal-Priest of S. Clemente. wuxuu soo daahay laba shir oo kala duwan oo uu ka qeyb galay
sanadihii 1914 iyo 1922, sababtoo ah waxay u baahnaayeen in ay ka gudbaan badweynta atlantik gaadiidkii yaraa ee waqtigaas. Wuxuu ka horyimid Pope Pius XI, kaas oo jawaab ahaan u kordhiyay waqtiga u dhexeeya dhimashada Pope iyo bilowga shirka. O'Connell wuxuu ugu dambeyntii awooday inuu kaqeyb galo shirkii xigay ee 1939, inkasta oo xilligaas safarka hawada la heli karo.