[1][2] Valerio Valeri was born in Santa Fiora, and studied at the Roman-Pio Seminary and the Pontifical Roman Athenaeum S. Apollinare, where he was made a professor in 1904.

[3] He received his episcopal consecration on the following 28 October from Cardinal Donato Sbarretti, with Archbishop Pietro Benedetti, MSC, and Bishop Giuseppe Angelucci serving as co-consecrators.

In August 1942, the nuncio disputed Marshal Pétain's claim that Pope Pius XII understood and approved of France's increased hostility towards the Jews.

[4][5] He was awarded the Grand Cross of the Légion d'honneur upon leaving France in 1944 to again work in the Secretariat of State, specifically the Congregation for Extraordinary Ecclesiastical Affairs.

Cardinal Valeri lived long enough to only attend the first session of the Second Vatican Council in 1962, and to participate in the conclave of 1963, which resulted in the election of Pope Paul VI.