The billionaire media magnate, 85, who is seeking national office again after a nine-year absence, has led four governments since entering politics in 1994 but was temporarily banned after a conviction for tax fraud in 2013.
Surrounded by a mounting debt crisis and scandal over Mr Berlusconi's "bunga bunga" sex parties in his villa outside Milan, his last government collapsed in 2011.
He told state radio on Wednesday he had been urged by "masses of people" inside and outside his Forza Italia party to run at the September 25 ballot.
"So I think in the end I will be a candidate for the Senate, so everyone will be happy," Mr Berlusconi said.
In his eighth national election campaign, he is again relying on the kind of full-throttled advertising that has helped to propel him to victory before.
Large screens in railway and underground stations around the country feature photos of a youthful-looking Mr Berlusconi alongside the slogan "Oggi piu che mai, una scelta di campo" — roughly translated to mean "Now more than ever, pick a side".
Forza Italia is considered to be the moderate arm of a conservative alliance dominated by two right-wing parties: Giorgia Meloni's Brothers of Italy, which leads in opinion polls, and Matteo Salvini's Italian League.
With its centrist and leftist opponents badly divided, the bloc looks on track to win a clear majority at the election, which was called after Mario Draghi's broad "national unity" government collapsed last month.
Mr Berlusconi's legal problems are not behind him. He is currently on trial on charges of bribing witnesses in a previous case, in which he was acquitted in 2014 of paying for sex with an underage prostitute.
Mr Berlusconi denies all wrongdoing.