DiCaprio, long an outspoken advocate for tackling the climate crisis, has supported Democratic candidates in the past.
In early 2020, he attended a fundraiser for Joe Biden at the home of former Paramount Pictures boss Sherry Lansing.
In the video posted on Instagram, DiCaprio praised Ms Harris’ ambitious goals of achieving net zero emissions by 2050 and helping to build a green economy.
He also noted her participation in the adoption of the Law on Reducing Inflation.
As vice president, Ms. Harris cast the deciding vote on President Joe Biden’s landmark climate law, which passed with only Democratic support.
With less than two weeks until Election Day, Ms. Harris has received the support of many celebrities, including Taylor Swift, Oprah Winfrey, Meryl Streep, Chris Rock and George Clooney.
She held a rally Thursday night in suburban Atlanta with former President Barack Obama and musician Bruce Springsteen. BeyoncĂ©, whose song Freedom is Harris’ campaign anthem, is expected to attend Harris’ rally in Houston on Friday.
Supporters of Republican Donald Trump include celebrities such as Elon Musk, Dennis Quaid, Roseanne Barr and Kid Rock.
In December 2016, DiCaprio and the head of his eponymous foundation met with Mr. Trump, then president-elect, to discuss how jobs focused on protecting the environment could boost the economy.