“Hi guys, here I am," said a beaming Mr Berlusconi in his first post on the social media site.
“There are five million of you on this platform and 60 per cent of you are under 30 years old … I feel a little envious, but my compliments all the same.”
Better known for dance videos and make-up tutorials, the Chinese-owned site has been embraced by a number of Italian politicians as the election campaign gathers pace.
Matteo Salvini, leader of the right-wing Lega Nord party and former interior minister, has more than half a million people following his prolific TikTok posts — a record for Italian politics, he claimed.
Another party leader, Carlo Calenda of the small centrist Action movement, told followers: “I can't give tips on make-up because I have a fat tummy and I am ugly, but I can talk to you about politics.”
Mr Berlusconi, a TV mogul who shook up Italian politics with his media-savvy showmanship and slick American-style rallies, is attempting his latest political comeback.
The leader of the centre-right Forza Italia party, he is running for a Senate seat and could join a coalition with Mr Salvini's League and Giorgia Meloni's Brothers of Italy party after the election.
He told his young audience on TikTok that he wanted to make Italy “a country that gives you new opportunities and the chance to realise your dreams”.
Three videos posted on his first day on TikTok showed him speaking to voters, playing with a smartphone and preparing for a TV interview as the September 25 election draws closer.
Mr Berlusconi, the former owner of AC Milan football club, served three separate terms as prime minister from 1994 to 1995, 2001 to 2006 and 2008 to 2011.
He was expelled from parliament in 2013 after a conviction for tax fraud, but a ban from public office was lifted in 2018.
A European Parliament election in 2019 gave him a route back to elected office, and he survived a series of health scares including a lung infection linked to Covid-19.
He flirted with a bid for Italy's figurehead presidency in January, before eventually deciding not to run, but the collapse of Mario Draghi's unity government has opened the door to another run for office.
Forza Italia is urging voters to back the party as a moderating, pro-European force in a potential hard-right coalition led by two anti-immigrant parties.
But Mr Berlusconi said last month he would support Ms Meloni as prime minister if her party wins the most votes: “If it is Giorgia, I am sure she will prove capable of the difficult task.”