After returning to America, he attended the University of Virginia School of Law and worked as an attorney and staffer to Senator Pete Domenici in Washington, D.C. Vaghi was then assigned as a seminarian to the Pontifical North American College, located in Rome, and attended the Pontifical Gregorian University in preparation for his ordination to the priesthood.
He was ordained in 1985, and designated a "Prelate of Honor" (entitling him to be addressed and referred to as "monsignor") by Pope John Paul II in 1995.
Vaghi has drawn attention because of his association with a number of highly influential conservative American jurists.
[1] He participated in the baptism and conversion to Catholicism of both Robert Bork, the unsuccessful conservative Supreme Court nominee, and columnist Robert Novak.
Vaghi is also active in the John Carroll Society, "an old-time Catholic service organization favored by Washington's large Catholic legal and political establishment," as whose chaplain he served as of 1987.