Bishop Francis Dunn received his B.A. degree at Loras College in Dubuque and studied theology at Kendrick Seminary, St. Louis. Bishop Dunn was ordained to the priesthood by Bishop Edward Fitzgerald in 1948 in his home parish in Elkader. He was associate pastor at St. Cecilia's Church in Ames from 1948-1950, served two years at St. Martin's Church in Cascade, and was then assigned to the Church of Nativity in Dubuque.

In 1956 Bishop Dunn was named Assistant Chancellor and also served as chaplain of St. Anthony's Home. From 1958 to 1960, he attended graduate school in Canon Law at the Angelicum University in Rome and received a J.C.L. Degree. Upon his return to Dubuque, he was named Chancellor of the Archdiocese, Archdiocesan Director of the Family Life Bureau, Director of Catholic Cemeteries, and Chaplain of Mt. Carmel Mother house. He was appointed Auxiliary Bishop of Dubuque and Titular Bishop of "Turris Tamalleni." In 1969 he was ordained a Bishop and was named Pastor of St. Joseph's Church in Dubuque. He also served as Chancellor and Vicar General of the Archidiocese.

Bishop Dunn was a member of the U.S. Bishops Committee on Pro Life Activites and was listed in the American Catholic "Who's Who" and "Who's Who in America." Dunn was an Executive Member of the United Way in Dubuque and the Chamber of Commerce.