Dolan, originally from St. Louis, attended St. Louis preparatory seminary south in Shrewsbury before graduating from Cardinal Glennon College, where he earned a bachelor's degree in philosophy. He then completed his priestly formation at the Pontifical North American College in Rome, where he earned a licentiate in sacred theology at the Pontifical University at St. Thomas.
Dolan was ordained in 1976 and served as an associate pastor at Immacolata parish in Richmond Heights until 1979 when he began studies for a doctorate in American church history at the Catholic University of America in Washington, D.C.
On his return to St. Louis, Dolan served in parish ministry from 1983-1987, during which time he was a liaison for the late Archbishop John L. May in the restructuring of the college and theology programs of the archdiocesan seminary system.
In 1987, hewas appointed to a five-year term as secretary to the Apostolic Nunciature in Washington, D.C. When he returned to St. Louis in 1992, he was appointed vice rector of Kenrick-Glennon Seminary, serving also as director of spiritual formation and professor of church history. During this time, he was an adjunct professor of theology at St. Louis University.
In 1994, Dolan was appointed rector of the Pontifical North American College in Rome. Additionally, he served as a visiting professor of church history at the Pontifical Gregorian University and as a faculty member in the department of ecumenical theology at the Pontifical University of St. Thomas Aquinas. The work of the archbishop in the area of seminary education has influenced the life and ministry of many priests of the new millennium.
In June 2001 - on the 25th anniversary of his ordination to the priesthood - he was consecrated a bishop and was named the auxiliary bishop of St. Louis by Pope John Paul II. In June 2002, he was appointed the 10th archbishop of Milwaukee by Pope John Paul II.