Member of the Parliament of Italy, 2001-2006

In 2001, Kessler was elected to the Italian Parliament as an independent member. He sat on the Committee on Justice Affairs and during his five-year term, he authored numerous bills on the International Criminal Court (ICC), the European Convention against corruption, the International Judiciary Cooperation and the European Arrest Warrant.

In addition to his committee assignments, Kessler was also a member of the Italian delegation to the Parliamentary Assembly of the Organization for Security and Co-operation in Europe (OSCE). From 2003 until 2006, he served as Vice-President of the Assembly. He participated in and led International Election Monitoring missions in the United States and in many other OSCE countries. In 2003, the OSCE Chairman-in-Office, Dutch Foreign Minister Jaap de Hoop Scheffer, appointed Kessler as his Special Representative during that year's parliamentary election in Armenia.^[2]

From 2006 to 2008, Kessler held the position of Italian High Commissioner to Combat Counterfeiting.

In December 2008, Kessler was elected member, and subsequently President, of the Legislative Assembly of the Autonomous Province of Trento.^[3] He resigned from this position before taking up the post of Director-General of OLAF in early 2011.

In 2009 Kessler started with Dieter Steger (SVP) and Herwig van Staa (ÖVP), chairmen of the legislative assemblies of South Tyrol and Tyrol, the project of a Euroregion that, for the three territories, would represent a recovery of historical Tyrol. The legislative assemblies of the autonomous provinces of Trentino and South Tyrol and Tyrol then unanimously approved the Euroregion Tyrol – South Tyrol – Trentino.^[4]

Head of OLAF, 2011-2017

In 2010, Kessler was nominated for the post of Director-General of OLAF, the Anti-Fraud office of the European Union.^[5] In late 2010, the European Parliament voted narrowly to put Kessler ahead of Thierry Cretin, an OLAF director. Later, the Council of the European Union decided that Kessler and Johan Denolf, from the anti-fraud unit of the Belgian judicial police, were their top two.^[6]

Kessler took office in February 2011 and soon became engaged in a comprehensive reform process to strengthen the efficiency of OLAF, aiming to step-up the fight against fraud and corruption in Europe. In 2012, he was elected President of the European Partners Against Corruption / European Anti-Corruption Network (EPAC/EACN), a formal network comprising close to fifty anti-corruption authorities from European Union Member States. The Network was set up to improve cooperation between authorities mandated with the fight against corruption in the European Union, as well as to foster closer relations between Member States and the European institutions.

Upon taking office, Kessler led the investigation into the 2011 cash for influence scandal in the European Parliament. During that time, OLAF was working closely with national authorities from Austria, Slovenia, Romania, Spain, Belgium and France; two MEPs – from Austria and Slovenia – resigned; a third was suspended by his party.^[7]

From 2012, Kessler oversaw the investigation that led to John Dalli, the then European health commissioner, losing his job over accusations that he asked for cash from a tobacco company in exchange for opening up the EU market to that company’s products. That investigation also ensnared Kessler, with Belgian authorities starting an investigation into allegations that he had broken the law during OLAF’s probe into Dalli. The European Commission lifted his immunity, opening him up to prosecution, prompting Kessler to launch legal action.

In his book "Hold up in Brussels, les lobbies au coeur de l'Europe" published in 2014, MEP José Bové told the story of how Giovanni Kessler, in connection with the then secretary general of the European Commission Catherine Day, covered what would later be proven to be false accusations of bribery which led to the resignation of Commissioner Dalli. In march 2016, the Belgian prosecutor's office required 14 months in prison and a fine against him. ^[8] As of July 2017, both the Belgian investigation and the case about his immunity were ongoing.^[9] They would later be dropped.

In 2013, he became a Member of the Executive Committee of the International Association of Anti-Corruption Authorities (IAACA). IAACA has more than three hundred organizational members which cover nearly all law enforcement national institutions and bodies entrusted with the task of fighting against corruption and more than two thousand individual members, including prosecutors, investigators and experts with experience in anti-corruption research or practice.

In 2014, Kessler became a member of the commission on appointment of the new bureau chief of the Ukrainian anti-Corruption Bureau.^[10]

In 2017, Marine Le Pen filed a lawsuit against OLAF and Kessler himself, charging that the anti-fraud office acted as a tool of President of the European Parliament Martin Schulz to undermine her and her party.^[11]

Head of the Italian Customs and Monopoly Agency, 2017–present

In July 2017, Kessler was appointed as head of the Italian Customs and Monopoly Agency in Rome.^[12]

Member of the International Anti-corruption Advisory Board in Ukraine (IACAB), 2017–present

In September 2017, Kessler joined the IACAB, which operates in the framework of the European Union Anti-Corruption Initiative in Ukraine.^[13]