The remark on Thursday, September 5, 2024, comes a day after Washington accused Moscow of seeking to influence the vote.
Putin often comments on political and social issues in the United States with sarcasm.
He said last year that the US political system was “rotten” and that Washington could not lecture other countries about democracy.
“Firstly, (US President Joe) Biden recommended all his supporters support Mrs Harris,” Putin said during a question and answer session at Russia’s Eastern Economic Forum in Vladivostok.
“Here, we are going to do that too, we’re going to support her,” he added, with a wry smile.
“She laughs so contagiously that it shows that everything is fine with her,” the Russian leader said.
“(Former US President Donald) Trump has imposed as many sanctions on Russia as any president has ever imposed before, and if Harris is doing well, perhaps she will refrain from such actions.”
In February, Putin backed Biden over Trump, calling the current president more “predictable”. The White House called on Putin to “stay out” of US elections.
Putin’s comments come a day after the United States indicted two employees of the state-run Russian news network RT and slapped sanctions on its top editors. Washington accused them of trying to influence the upcoming US ballot.