He was the son of his internationally renowned father, Emilio Diena, who was regarded by many as “Italy’s greatest philatelist.” Because of his in-depth knowledge and study of the stamps of Italy, he wrote numerous articles on stamps of Italy, especially the early “classic” issues.

Diena was highly regarded by fellow philatelists, both buyers and sellers of stamps, because of his ability to detect counterfeit or fake copies of the early rare Italian postal stamps.

His opinion was always held with the highest regard by fellow collectors.

Diena was named to the American Philatelic Society Hall of Fame in 1978.

His son Dr. Enzo Diena continued on with his father's work.