Stefano was Diplomatic Advisor to the President of Italy, Giorgio Napolitano, Italian Permanent Representative at NATO and Deputy Chief of Mission at the Italian Embassy in Washington. He also served in Perth, Western Australia; New York (United Nations) and Moscow.
Stefano sits on the Board of Directors of the European Leadership Network in London, the Board of Directors of the Center for American Studies in Rome, and is non-resident Senior Fellow of the Brent Scowcroft Center for International Security at the Atlantic Council. He was also Vice Chairman of Italian defence company OTO Melara.
He was a Lieutenant in the Alpine corps of the Italian army, and a recipient of the Grand Cross of the Order of Merit of the Italian Republic. He also has honours from the governments of France, Brazil, Germany, Argentina, Morocco and South Korea.