Leonardo was 2019 Fulbright Research Scholar at the Fletcher School of Law and Diplomacy (Tufts University, MA, USA) and is currently NWO Research Scholar at the School of Law of the Erasmus University of Rotterdam.
Since 2012 a member of the Department of Legal Studies of Bocconi University and a Faculty Member of the PhD in Legal Studies. He is part of the United Nations Expert Group working on Anti-Corruption Academic materials (Academic Initiative Against Corruption-UNODC); Research Fellow for the Research Centre on International Cooperation Regarding Persons Sought for Corruption and Asset Recovery established by the G20 at the Beijing Normal University and member of the Wolfson College (University of Cambridge, UK). In 2021 he obtained the Italian National Scientific Qualification as Full Professor in International Law (ASN-I Fascia) by unanimous decision of the Commission.
Apart from his academic appointments, Leonardo has served the International Monetary Fund (IMF) as a Technical Assistance Specialist and authored and co-authored reports commissioned by the Council of Europe, the European Commission, the Inter-American Development Bank (IADB), the World Bank (Public Accountability Mechanism), and the United Nations Office on Drugs and Crime (UNODC). He was a member of the Italian delegation to the V Conference of State Parties of the United Nations Convention against Corruption (UNCAC) and took part as an expert invited to the OECD Working Group on Bribery, the Implementation Review Group of the UNCAC, and the Group of States against Corruption (GRECO) of the Council of Europe.