He is best known for his monumental Italia sacra, a massive nine-volume treatise detailing the history of all Italian dioceses from the earliest Christian centuries to his day.

He entered the Cistercian Order in 1610 and was sent to the Gregorian University in Rome, where he studied under the Jesuits Francesco Piccolomini and John de Lugo.

In the 1620s Ughelli worked, together with the Luke Wadding, Andrea Vittorelli, Girolamo Aleandro, and Cesare Becilli to the revision of Ciacconius' Vitae et Res gestae Summorum Pontificum et S.R.E.

[5] He was a consultor of the Index Librorum Prohibitorum and theologian to Cardinal Giancarlo de' Medici; he was frequently offered the episcopal dignity, which he refused.

[3] Ughelli's work was abridged by Giulio Ambrogio Lucenti (Rome, 1704) and republished, with corrections and additions, by Nicola Coleti (10 vols, Venice, 1717-22).

Ughelli's work exerted a great influence on Gams' Series episcoporum ecclesiæ catholicæ (1873-86) and on Eubel's Hierarchia Catholica Medii Aevi (1913–1967).