Jannuzzi began his journalistic career at L'Espresso and in 1967, together with his colleague Eugenio Scalfari, published the investigation on the military secret services involved in the attempted coup d'état known as Piano Solo.

[3] From 2001 to 2008, Jannuzzi held once again a seat in the Senate, elected with Silvio Berlusconi's Forza Italia, who granted him parliamentary immunity from several judicial controversies he was involved in.

At the end of the 1990s, Jannuzzi was investigated for some articles in which he expressed numerous criticisms of the Neapolitan magistracy concerning the case of Enzo Tortora, considered a victim of a very serious judicial error.

[5] On 19 October 1991, Jannuzzi accused judge Giovanni Falcone, who was trying to get the licenses to create a power of contrast against the Mafia associations, of being the main one responsible for the inability of the country institutions to fight Cosa Nostra.

Without any kind of evidence of the plot, Jannuzzi, Mondadori and the publishing house of Il Giornale were all sued, with the last two sentenced to a total reimbursement of €350,000.