Borgongini Duca was born in Rome, and studied at the Pontifical Roman Seminary, from where he obtained doctorates in theology and in canon and civil law.

He was favorably impressed by a young American seminarian named Francis Spellman,[1] whom Duca would later assist in consecrating as Auxiliary Bishop of Boston in 1932.

He was raised to the rank of privy chamberlain of his holiness on 2 March 1917, and was named pro-secretary of the Sacred Congregation for Extraordinary Ecclesiastical Affairs on 28 June 1921, rising to become full secretary on 14 October 1922 (the pope was the nominal head of that dicastery).

He received his episcopal consecration on the following 29 June from Cardinal Pietro Gasparri, with Archbishop Carlo Cremonesi and Bishop Agostino Zampini, OSA, serving as co-consecrators, in the Hall of Benedictions at St. Peter's Basilica.

In early 1937, he bestowed the Golden Rose on Queen Elena of Italy, on the occasion of her fortieth wedding anniversary to Victor Emmanuel III.