The "Titanic" actor marked the milestone with a gala event at Jackson Park Ranch in Santa Rosa, California, which featured a lavish dinner, a fine art auction and a performance by the Coldplay rocker. Other stars who attended included event chairs Arnold Schwarzenegger, Ellen DeGeneres, Tobey Maguire, Edward Norton, Moby and Robert Redford.
Celebrating his two decades of activism, the 43-year-old told attendees that he had founded his Leonardo DiCaprio Foundation "based on the simple idea" that he could make a huge difference by raising funds for the "most effective environmental projects" around the globe.
He then went on to announce $11 million (£8.4 million) in new grants to environmental projects - taking the amount handed out by him to more than $100 million (£76 million).
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Thank you @jacksonfamilywines, @bankofamerica, and @tiffanyandco for celebrating @leonardodicapriofdn’s 20th Anniversary and for your continued support and efforts to protect our planet. Additional thank you to our art partners: Lisa Schiff of @sfaadvisory, @sothebys, and @invaluableofficial. Photo Credit: Getty.
The Hollywood superstar received a roasting on stage from Chris, who performed Celine Dion's "My Heart Will Go On", the theme tune to "Titanic", and mocked Leonardo's love of cargo shorts.
"This is a guy, he's seen cargo shorts and he said, 'I'm going to save these shorts from extinction,'" the musician quipped in footage posted by one attendee to Instagram. "They should have gone out about 25 years ago."
According to The Hollywood Reporter, the event raked in $8 million (£6.1 million) for good causes, with $500,000 (£380,000) coming from ticket sales and $7.5 million (£5.7 million) raised by an auction with lots that included paintings and sculptures from the likes of Ai Wei Wei, David Hockney, Frank Gehry and Wayne Thiebaud, who was also presented with a Lifetime Achievement honour.
At the event, Leonardo announced the appointment of famed primatologist Jane Goodall, 84, to his foundation's board.
The star and his foundation have also made donations to help prevent forest fires in California, and relief funds for Hurricane Florence.