He is best known for being a senior advisor to former prime minister Silvio Berlusconi, of whom he became a secretary in his early 20s and since the 1970s had worked for him at his many companies, including Publitalia '80 and Fininvest Rai.

In 1964, at the age of 23, he worked as secretary for Berlusconi, who with his Edilnord company sponsored Torrescalla, a small student category football team linked to the Rui Foundation, of which Dell'Utri was coach.

[2][3] In 1965, Dell'Utri moved to Rome, where for a couple of years he directed the ELIS Sports Group in the Tiburtino-Casal Bruciato district at the International Centre for Working Youth, an apostolic initiative of the Catholic Church that the Pope entrusted to Opus Dei.

In 1967, he returned to Palermo at the Athletic Club Bacigalupo; during this experience, as admitted by Dell'Utri himself, he met Vittorio Mangano and Antonino Cinà, two mafiosi belonging to Cosa Nostra.

In 1980, he was called by Berlusconi and worked for Publitalia '80, the advertising sales wing of Fininvest's television division, first as a manager and later as the company's chairman and chief executive.

[31] On 24 October 1976, Dell'Utri was together with Mangano and other mafiosi at the birthday party of the Catania boss Antonino Calderone held at the Le Colline Pistoiesi restaurant in Milan.

Dell'Utri was acquitted by the Supreme Court of Cassation on the grounds that the president of Trapani's basketball team also knew the Virga boss and did not perceive him as a Mafia threat.

The sentence stated that Dell'Utri had "mobilized [two] mafiosi of the caliber of Virga and Buffa" to "convince" the Garraffa "to respect the commitment", a refund of money as part of a sponsorship, and he was acquitted because there was not enough evidence that the visit of the two to Garaffa was "capable of instilling fear".

He said Giuffrè had perpetuated the trend that every new turncoat would attack Dell'Utri and the former Christian Democracy prime minister Giulio Andreotti in order to earn money and judicial privileges.

[11][12][13] In January 1996, while he was charged in Turin for false invoices and tax fraud and under investigation in Palermo for Mafia association, Dell'Utri became a Forza Italia deputy in the Italian Parliament.

In the five years of activity in the Chamber of Deputies, he presented only two law degrees: a reform of the legislation on the dairy industry and changes on the protection of minor victims of abuse or violence.

[56] On 10 September 2007, he joined the board of directors of E Polis,[57] which at the time was the publisher of 15 free-press newspapers throughout Italy,[58] including the Circolo Dell'Utri,[59] and became president of the advertising agency Publiepolis spa.

Out of the 12 proceedings, Dell'Utri was acquitted four times at the Supreme Court of Cassation (attempted extortion, incitement to multi-aggravated slander, embezzlement, and the State-Mafia Pact); he was acquitted once for not proceeding due to an error by the Prosecutor's Office (tax fraud while he had been acquitted for bankruptcy); he once agreed to a plea bargain (false invoices and tax fraud); he received a definitive sentence of conviction twice (7 years of imprisonment for external complicity in a Mafia association, serving 4 years in prison and more than 1 year under house arrest, and 8 months for building abuse); he was once sent to trial but this was covered by the statute of limitations (the case related to the refoundation of Propaganda Due, or P2, through the P3); he was twice given a dismissal (corruption and receiving stolen goods); and still had a pending investigation for extortion of Berlusconi before the latter died in June 2023.

With the coordination of the services of the Anti-Mafia Investigative Directorate and through the cross-referencing of information relating to telephone records and the results of a credit card in his possession used for payments and consequently arrested inside a hotel in Beirut, Lebanon, Dell'Utri was located on Lebanese territory on 12 April 2014.

[73] Following the ruling of the Supreme Court of Cassation, the General Prosecutor's Office notified the imprisonment order in execution of the sentence for the crimes charged against Dell'Utri and completed the documentation sent to the Lebanese judicial authority for the purposes of extraditing him to Italy.

[36][80][81] According to the motivation of the first-instance sentence,[nb 1] Dell'Utri provided "a concrete, voluntary, conscious, specific and precious contribution to the illicit goals of Cosa Nostra, both economically and politically".

The bill would have also removed the possibility of prison sentences being handed to those found guilty of aiding individuals involved in a Mafia association if no financial advantage was gained from this assistance, and the draft legislation would have further prevented prosecutors from wiretapping the conversations of people suspected of doing this.

The Third Criminal Section of the Appellate Court of Palermo declared Dell'Utri a fugitive when it was discovered he had left the country shortly ahead of the impending final sentence.

The Supreme Court of Cassation convicted Dell'Utri of acting as a go-between for the Sicilian Mafia and the Milan business elite, including Berlusconi's companies, from 1974 to 1992.

[89][90] On 13 June 2014, Dell'Utri was extradited to Italy and booked into a prison in Parma,[91] where he began serving his seven years sentence under a high-security regime.

[94] In July 2018, he was moved to house arrest in Milan due to health issues;[95][96][97] he suffered from heart disease, a severe form of diabetes, and prostatic adenocarcinoma.

In the tapped phone conversation, Palazzolo urged his sister to pressure Dell'Utri to disrupt the extradition attempts and offered to cut him in on construction deals in Angola.

"[106][107] On 15 May 2007, the Appeal Court of Milan sentenced Dell'Utri and Mafia boss Vincenzo Virga to two years each for attempted extortion of Trapani Basket Ball team by Publitalia, the Fininvest concessionaire.

In reviewing the previous sentence, the appeals court said that the conviction stood for acts committed by Dell'Utri prior to 1992, while he was acquitted for charges after that year.

"[113] On 31 October 2017, Dell'Utri was enrolled in the register of people involved in underground negotiations between corrupted representatives of the Italian government and the mafia organizations in sicily (State-Mafia Pact) upon request of the public prosecutor, having the prosecutor's office obtained new relevant informations coming from the transcripts of telephone conversation in Palermo by Graviano involving Dell'Utri together with other people implicated in the negotiations.

[115] According to the sentence, issued after three days of deliberation, the State-Mafia Pact was real but was not a crime, and thus Dell'Utri and other defendants were acquitted; the Mafia bosses were convicted for extortion.

On 11 February 2007, Dell'Utri announced that he had received from the children of a deceased partisan (whose name he refused to reveal) five alleged diaries handwritten by Benito Mussolini, containing notes from 1935 to 1939.

Some historians, such as Francesco Perfetti, initially showed themselves to be possibilists; others, such as Giovanni Sabbatucci, Valerio Castronovo, Emilio Gentile, Luciano Canfora, and Denis Mack Smith were sceptical.

After several months of studies conducted by Gentile and the Italian graphologists president Roberto Travaglini, macroscopic historical discrepancies and handwriting that cannot be traced back to Mussolini were found.

"[121] Ezio Cartotto, who was Dell'Utri's collaborator, stated before the judges of Caltanissetta and Palermo: "Every now and then [Dell'Utri] would blurt out against Berlusconi, and once he told me 'Silvio doesn't understand that he has to thank me, because if I were to open my mouth I...'"[122][123] These words were interpreted by some journalists, including Marco Travaglio, Daniele Luttazzi, and Carlo Freccero, who were acquitted from the charges of forgery and slander for what they stated during the 2001 interview with Travaglio at Satyricon, as a sort of threat towards Berlusconi to urge him to find legislative solutions before the Supreme Court of Cassation ruling.