After graduating, Connell won a scholarship to the Jesuit Boston College and attended for 2 years.
[1]: 77 Connell spent novitiate year at the Redemptorist house in Annapolis, Maryland, after which he was sent to Mount St. Alphonsus Seminary in Esopus, New York to study philosophy and theology in preparation for priestly ordination.
On June 26, 1913, he was ordained at Mount St. Alphonsus by Thomas Francis Cusack, auxiliary bishop of the Archdiocese of New York.
From August 14, 1913, to February 15, 1914, he did a second novitiate in Annapolis and was assigned as a curate to Our Lady of Perpetual Help church in Brooklyn, NY.
With his dissertation De scientia beata Christi he obtained a Doctorate in Sacred Theology summa cum laude.
On returning to the United States, was assigned for a short time to his previous parish in Brooklyn.
[1]: 75 From 1945 until 1950, he also served as rector of Holy Redeemer College, in Washington, D.C. During the 1940s, he was a charter member and first president of the Catholic Theological Society of America.
[3] By 1949 Connell had risen to Dean of the School of Sacred Theology at Catholic University and remained until 1957.
He was on the American Bishops' Press Panel which briefed English-speaking reporters of conciliar proceedings.
Connell claimed that through his teaching, letters, retreats, and conferences, he had come into contact with one-quarter of the priests in the United States.
He was generous with his time and at the request of students would hold a study review sessions in the evening before an exam.
[citation needed] Connell regularly spent his summers at the San Alfonso[4] Redemptorist retreat house in Long Branch, New Jersey.
[citation needed] By his own admission, the chief theological influences on him were dogmatic theologians Reginald Garrigou-Lagrange, O.P., and Fr.
Gerardus Cornelis Van Noort (d. 1946); and moral theologians St. Alphonsus Liguori, B. Merkelbach, O.P., and Regatillo-Zalba, S.J.