His father was a leader of the Irish American Catholic community, published a small newspaper and was active in Republican circles.

He was attending Peru High School when, in 1905, his father was named by President Theodore Roosevelt as the United States consul to Uruguay.

During his tenure at Notre Dame, he brought numerous refugee intellectuals to campus; he selected Frank H. Spearman, Richard Reid, Jeremiah D. M. Ford, Irvin Abell, and Josephine Brownson for the prestigious Laetare Medal.

O'Hara strongly believed that the Fighting Irish football team could be an effective means to "acquaint the public with the ideals that dominate" Notre Dame.

He wrote, "Notre Dame football is a spiritual service because it is played for the honor and glory of God and of his Blessed Mother.

President Franklin D. Roosevelt later appointed O'Hara to the board of visitors of the Naval Academy in Annapolis, becoming the first Catholic bishop to be so honored.

Succeeding the late John A. Duffy, O'Hara greatly expanded Catholic education in the diocese, and eliminated racial segregation in schools and churches.

[1] Differing in style from his predecessor, Cardinal Dennis Joseph Dougherty, he often answered his own doorbell, which he explained by saying "How else can I meet the poor?

He condemned the Supreme Court's ruling against banning the films La Ronde and M.[7] Moreover, not overly favorable of radio and television, he suggested that Catholics sacrifice such entertainment for Lent.

[8] Pope John XXIII created O'Hara a Cardinal in the consistory of December 15, 1958, and appointed him a Cardinal-Priest with his titular church the Basilica of Ss.