After attending the regional seminary at Benevento, he moved to Rome to complete his formation at the Gregorian University and then at the Pontifical Ecclesiastical Academy.
Ordained priest on 17 December 1938, he first worked for a period at the Secretariat of State. Then, in 1947, he was sent to the Apostolic Internunciature of China, where he remained until September 1951 when he was expelled by the communists, after having suffered 3 months of house arrest. For over three years he was auditor at the apostolic nunciature in Belgium; then visitor and later, regent of the apostolic delegation in South Vietnam. Promoted Internuncio in China with residence in Formosa in 1959, and on 14 October 1961 he was appointed titular archbishop of Apollonia. On 17 December of the same year he received episcopal ordination.
In 1967, he was nominated apostolic pro-nuncio in India. In February 1968, he served as head of the delegation of the Holy See at the 2nd United Nations conference for commerce and development (UNCTAD) held in New Delhi.
In April 1969, he was called as responsible of the secretary of the Administration of the Patrimony of the Holy See. On 14 June 1977, he was entrusted the office of Substitute of the Secretariat of State. Thereafter, on 30 April 1979, he was appointed President of the Administration of the Patrimony of the Holy See.
He then served as President of the Prefecture for the Economic Affairs of the Holy See from 30 January 1981 until 22 January 1990.
He was Grand Master of the of the Equestrian Order of the Holy Sepulchre of Jerusalem from 15 November 1988 until 21 December 1995.
Created and proclaimed Cardinal by Pope John Paul II in the consistory of 30 June 1979, of the Title of S. Maria della Vittoria (St. Mary of Victory) [protodeacon of Saint Mary Auxiliatrix in Via Tuscolana until 26 November 1990].
Cardinal Giuseppe Caprio died on 15 October 2005.