Michele Valensise began his diplomatic career in 1975.
In the Ministry of Foreign Affairs, Valensise served in the Directorate General of Economic Affairs. In 1978, he was sent to the Italian Embassy to Brazil, as the director for the sector of economics and press. In 1981, he was transferred to the Embassy in Bonn, with his expertise in European Political Cooperation.
From 1984 to 1987, during the civil war in Lebanon, he was a Councilor to the Italian Embassy in Beirut, as the Deputy to the Head of Mission.
He returned to Rome, form 1987 to 1991 as the head of the Secretariat of the Undersecretary to the Exterior, Susanna Agnelli.
From 1991 to 1997, in Brussels Valensise was the permanent representative from Italy to the European Union following the relations with the Mediterranean countries and the Balkans.
At the beginning of 1997, Valensise was transferred to Sarajevo as the Ambassador of Italy to Bosnia Herzegovina, immediately after the cessation of hostilities and the deployment of the multinational Stabilization Force.
In Rome in 1999 he was the head of the Office for the relationship with Parliament and then the head of the Cabinet of Minister Lamberto Dini.
From 2001 to 2004 he was the head of Press and Information Services and the spokesperson for the Ministry of the Exterior.
From 2004 to 2009, Valensise was he Ambassador of Italy to Brazil. In the spring of 2009, he was named Ambassador of Italy to Berlin.
From July 2012 to March 2016, he was the Secretary General of the Ministry of Foreign Affairs. Since April of 2016, he was served as the Vice President of Astaldi SpA.