After studying Catholic theology and philosophy Sardi received on 29 June 1958 in Acqui the sacrament of Holy Orders. After graduation, he received his doctorate from the Catholic University of Sacro Cuore in Milan in the canonical and in the general law. This was followed up to 1976, a lecturer in moral theology at the University of Turin. He then joined the diplomatic service and was appointed to the State Secretariat. Pope Paul VI. gave him on 30 June 1978 the honorary title of chaplain of His Holiness ( Monsignor ); on 24 December 1987, Pope John Paul II awarded him the title of Honorary Prelate of His Holiness. In 1992 he became Deputy Assessor, appointed assessor of the Section for the general affairs of the Vatican Secretariat of State in 1997.
On December 10, 1996 by Pope John Paul II appointed Titular Archbishop of Sutrium and prosecuted ex officio of the State Secretariat as Nuncio for special tasks, donated to him on 6 January 1997 the Pope consecrated bishop. Co-consecrators were the Archbishops Curia Miroslav Stefan Marusyn and Giovanni Battista Re. On 23 October 2004, Pope John Paul II appointed Vice - Camerlengo. He was also a longtime head of the translation department for over thirty years and was responsible for the Pope speeches.
Sardi 's Honour and Devotion Grand Cross of the Order of Malta - Bailli. Pope Benedict XVI. ordered him on June 6, 2009 in succession to Cardinal Pio Laghi to Pro- Patron of the Order of Malta. Its patron Cardinal Sardi was after the award of the cardinalate in 2010.
In solemn consistory of November 20, 2010 it took Benedict XVI. as cardinal deacon with the title Diakonia Santa Mary Help of Christians in via tuscolana in the College of Cardinals. On January 22, 2011, Pope Benedict XVI. Paolo Sardi, the argument put forward on grounds of age resignation from the office of Vice - Camerlengos to.