Many of his writings, including the tripartite Introduction to Italian Sculpture, and his magnum opus, Donatello: Sculptor, are regarded as classics in the field.

Born into an Irish Catholic family in the Belgravia district of Central London, Pope-Hennesssy's father was Major-General Richard Pope-Hennessy, who was the son of the politician Sir John Pope Hennessy.

Upon graduation, Pope-Hennessy embarked his journeyman years by travelling in continental Europe and becoming acquainted with art collections, both public and private.

[4] Initially, he went to Tuscany, but was enticed by an offer from the Metropolitan Museum of Art to head its department of European painting, and moved to New York City.

Besides his own scholarly publications, some of which became classics and were often reprinted, and his responsibilities as a museum director, he provided his name and expertise for others (such as Sotheby's or the Collins Encyclopedia of Antiques).

Hence, he retired at the age of seventy-five and moved permanently to Florence with his lover, Michael Mallon,[9] and resided at Palazzo Canigiani, where he died five years later.