De Luca was born on Christmas Day, 25 December 1876 in Rome, the son of a blacksmith. He sang in church choirs as a boy. After his voice broke, a wealthy patron paid for him to have singing lessons at the Rome Conservatory, where he studied with two top-class pedagogues, Venceslao Persichini (who also taught De Luca's fellow baritone stars Mattia Battistini and Titta Ruffo) and Antonio Cotogni. He made his operatic debut at Piacenza in 1897, singing Valentin in Gounod's Faust. His debut proved a success and he was invited to sing at a string of more important venues.[citation needed]
De Luca was renowned as a master of lyric, smooth-toned legato singing and his recordings confirm his excellence in this regard. A small man, De Luca lacked a voice of huge dimensions; but his voice was immaculately used and had ample carrying power in even the largest theatres. During De Luca's best years his voice also possessed exceptional beauty of tone, in the middle register particularly. He was a clever and versatile actor, too, and was considered to be especially memorable in ebullient comic roles.[citation needed]
He appeared at Italy's foremost opera house, La Scala, Milan, from 1902 to 1910, and made his London debut at the Royal Opera House, Covent Garden, in 1907. Subsequently, De Luca moved to America where he became a leading baritone at the Metropolitan Opera for 20 years, from 1915 to 1935. (He returned briefly to the Met in 1939–1940.) His first appearance at that house was on 25 November 1915, as Figaro in The Barber of Seville with Frieda Hempel as Rosina and Giacomo Damacco as Count Almaviva, with Gaetano Bavagnoli conducting.[citation needed]
The illustrious conductor Arturo Toscanini is reputed to have once called De Luca "absolutely the best baritone I ever heard".[3] Certainly, he was praised by critics and audiences alike in a wide range of operatic roles, ranging from buffo and bel canto parts through to the core Verdi and Puccini characters. He even made some early forays into Wagner during his days at La Scala (Like several Italian singers of that era, he eschewed the German language, singing only in Italian and French).