[1] In 1849, when Bishop Michael O'Connor traveled to Dublin, to recruit volunteers for missionary work in America, Tuigg was the first to respond.

Pope Pius IX decided to make Tuigg the new bishop of Pittsburgh and would not accept any declination of the honor.

At the time, the combined Pittsburgh and Allegheny dioceses contained 133 churches and 191 chapels, convents, and educational institutions.

[2] It may be said of him that he combined the qualities of firmness and gentleness to a degree rarely found in the same individual; strong and unyielding when confident of the justice and propriety of any position he took, he was at the same time kind and courteous to those from whom he differed.

Proofs of his executive ability, his piety, and his self-sacrificing zeal abound throughout the diocese over which God called him to rule, and which he left in better condition than it had known for some years.