Valerio Valeri studied in Rome, the subjects Catholic theology and philosophy. He received on 21 December 1907, the sacrament of Holy Orders, and then worked as a lecturer at the Department of Fano. From 1904 to 1920 he was professor of theology in Rome, during the First World War he rendered service as a military chaplain. In 1920 he entered the service of the Vatican Secretariat of State in 1921, he worked for the Apostolic Nunciature in France.
1927 Pope Pius XI appointed him. Titular Archbishop of Ephesus and appointed him as Apostolic Delegate to Egypt and Arabia. He received his episcopal consecration Donato Raffaele Cardinal Sbarretti Tazza. In 1933 he was sent by Pope Pius XI. as Apostolic Nuncio to Romania, 1936, he gave him the same task in France. At the end of his service in France in 1944 Valerio Valeri was awarded the Grand Cross of the Legion of Honour. From 1944 to 1948 he worked in the department for special ecclesiastical affairs within the Vatican Secretariat of State.
1948 Pope Pius XII appointed him. Assessor of the Congregation for the Oriental Churches and 1950 as President of the Central Committee for the preparation and conduct of the Holy Year. On January 12, 1953 Valerio Valeri by Pope Pius XII. taken as a cardinal priest with the titular church of San Silvestro in Capite in the College of Cardinals and appointed Cardinal Prefect of the Congregation for Religious. He participated in the first session of the Second Vatican Council.
Valerio Valeri died on 22 July 1963 in Rome and was buried in the crypt of his family in Santa Fiora.