Silvestri was the President of the Italian International Affairs Institute from 2001 to 2013.
Between January 1995 and May 1996, Stefano Silvestri served as Under Secretary of State for Defence, having previously been an Advisor to the Under Secretary of Foreign Affairs for European matters and a consultant to the Prime Minister's Office under various Governments. He continues to act as a consultant to both for the Ministry of Foreign Affairs and the Ministries of Defence and Industry.
Between 1971 and 1972, he worked at the International Institute for Strategic Studies in London. From 1972 until 1976 he held the post as Professor for Mediterranean Security Issues at the Bologna Centre of Johns Hopkins University. A journalist by profession, he was a member of the Policy Committee of Europeo in 1979, a special correspondent and columnist for Globo in 1982 and has contributed articles on foreign and defence policy to numerous national daily papers. He was a member of the Trilateral Commission.