He was the third child of Italian poet Gabriele D'Annunzio and Roman aristocrat Maria Hardouin di Gallese.
He graduated in mechanical engineering and, after WWI, was hired by automotive firm Isotta-Fraschini.
He moved to the US as representative of the firm and later became senior manager and vice-president of American Aeronautical Corporation of Enea Bossi. In 1930 he took US citizenship.
- "Fisicamente, quest'uomo prestante, rosso di capelli e dalla mascella squadrata, gli assomilgiava abbastanza poco..." [Physically, this good-looking man, with red hair and a square jaw, didn't look like him very much.] https://books.google.it/books…