A native of the diocese of Asti, Italy, he was ordained a priest there in 1950. In 1959 he moved to Rome and entered the direct service of the Holy See, serving as a secretary of nunciatures in Latin America and achieving the title of monsignor (he was named a Chaplain of His Holiness the day Pope Paul VI was elected) before becoming an official of the Roman Curia's Council for Public Affairs of the Church in 1968.
On November 30, 1977 he was appointed a titular archbishop and the nuncio to Chile, one of the countries where he had served as nunciature secretary. He returned to Asti to be consecrated a bishop before taking up his post. He returned to Rome in 1988 as Secretary of the Council For Public Affairs of the Church, which in 1989 became the Section for Relations with States of the Secretariat of State. (The occupant of this post is sometimes informally called the "Vatican foreign minister").
In 1994 the Pope named him Cardinal-Bishop of the suburbicarian see of Albano, and on November 30, 2002, exactly twenty-five years after he was first appointed a bishop, he was elected vice-dean of the College of Cardinals in succession to Joseph Cardinal Ratzinger, who became Dean.
When he turned 75 in 2002 the Pope specifically invited him to stay on as Secretary of State, though this is the customary retirement age for heads of major Vatican departments (there is no retirement age for the Deanship or Vice-Deanship). He is close to the present Pope, though some have called him a less distinguished Secretary of State than his predecessors.
He is not seen as a likely future Pope, and being past the customary retirement age it is probable that a new Pope would not wait long before naming a new Secretary of State.