Sobchak vehemently denied that her plan to run in the March elections, which she announced last week, was a Kremlin plot to boost interest in the polls.
Holding her first news conference in a trendy theatre in central Moscow, Sobchak stressed that she was not a professional politician and said her programme would be developed with the help of experts and supporters.
"I'm putting myself out there and I'm saying that I'm against what is happening in the country," she said.
Sobchak, who is the daughter of Putin's late mentor, former Saint Petersburg mayor Anatoly Sobchak, is seeking to promote herself as the choice for Russians who are "against all" candidates.
Before 2006, Russian elections allowed voters to reject the list of candidates by ticking a box titled "against all".
"These elections should become a national referendum in which the 'against all' candidate would unite people," she said.
Russian TV host Ksenia Sobchak. Source: AAP
Sobchak said she needs to collect 100,000 signatures to be formally put on the ballot. So far just over 9,200 have signed, according to her website.
A former host of reality show Dom-2, in which young people lived together and formed couples, Sobchak rejected ridicule of her past job, saying "our parliament is a much funnier place than Dom-2".
'Quasi-elections'
Sobchak repeated a promise to drop out of the race if opposition leader Alexei Navalny was allowed to run.
Putin's 18 years in power resulted in a lack of freedom including free courts and free elections, she said, adding that polls should be open to all, including Navalny.
"I will try my best to get him registered," Sobchak said. "If he is registered I will withdraw my candidacy."
However, she said she would "not personally offend Putin" despite disagreeing with his policies, because he had helped her late father.
Navalny has declared his intention to run for president and campaigned across Russia, mustering several mass rallies against the Kremlin despite attacks on his supporters.
Authorities say he is not eligible to put his name on the ballot due to a controversial conviction for fraud, widely seen as a political ploy.
"What we have now are not elections, they are quasi-elections... it's an expensive show of rather low quality," Sobchak said. "But we must still try to fight."
Political analysts have said Sobchak's bid was designed by Putin's team to rekindle public interest in a dull election expected to extend the president's term to 2024.
Sobchak said a "huge number of businessmen" had expressed a desire to help her campaign, which is headed by Igor Malashenko, a former head of Boris Yeltsin's 1996 presidential campaign.
Sobchak announced her presidential bid earlier this month. Source: AAP
His decision to join Sobchak's staff has already generated high drama as his partner, socialite Bozhena Rynska, supports Navalny and wrote on Facebook that she is "in shock" and would ponder whether to leave him.
Sobchak's internet campaign chief is Vitaly Shklyarov, a veteran of the 2016 US presidential election where he was a political consultant for Senator Bernie Sanders.
