Loras realized that his health was failing and he requested a coadjutor bishop from the Holy See. On January 9, 1857 Pope Pius IX named Smyth the Titular Bishop of "Thennesus" and Coadjutor Bishop of Dubuque. Because of the time involved in sending communications, the papers from Rome did not arrive in Dubuque until April, 1857. On May 9, 1857, Smyth was consecrated by Peter Richard Kenrick, Archbishop of St. Louis. John Henni, Bishop of Milwaukee, and Anthony O'Regan, Bishop of Chicago, served as co-consecrators.