In addition to his memorable roles on screen, the late
The 63-year-old, who died on Monday of an apparent suicide, was known for his charity work at organizations such as Comic Relief, the Christopher & Dana Reeve Foundation, the LiveStrong Foundation, St. Jude Children's Research Hospital and more.
"There were so many ways and so many things he did for so many people," Katzenberg told the Times in an interview. "He really had just a giant heart and that's what makes me so sad."
Beginning in 1986, Williams, alongside fellow actor-comedians
"When we started [Comic Relief], we had to figure out what would be a suitable cause. Nobody was more adamant than Robin that it should help the homeless," Bob Zmuda, creator of Comic Relief, told The Times in a phone interview.
"Robin came from a family with money -- he was brought up with a silver spoon in his mouth, and I think he felt so blessed that he wanted to do something for people who weren't brought up like that."
Zmuda said because of Williams, Goldberg and Crystal, Comic Relief has raised more than $80 million.
"Robin was -- you light a match and he'll start performing," Zmuda recalled.
The Comic Relief shows even influenced a generation of comics.
"When I was 18 I got a job as an intern at Comic Relief just to be near him," tweeted filmmaker Judd Apatow on Monday. "A genius and a truly kind man who made the world a better place."
Williams was also a big supporter of the Reeves foundation, which is dedicated to curing spinal cord injury. Williams lived with Christopher Reeve while studying acting at Juilliard in New York.
"While the world knew Robin Williams as an Oscar-winning actor, we knew a different side to the man whose smile was as big as his heart," said Reeve Foundation President and CEO Peter Wilderotter in a statement.
The Reeve family shared similar memories of the late actor.
"The world knew Robin as a comedic titan, but to our family, he was simply one of our Dad's dearest friends," the family said in a statement on the foundation's website. "From the moment they were classmates at Juilliard, their friendship transformed into a brotherhood that was built on a mutual admiration for the theater, the arts and, most importantly, laughter."
FOR THE RECORD
This post has been updated to include a statement from the Reeve family and foundation CEO Peter Wilderotter.
One well-known part Williams played was a medical student who spread humor to his patients in the 1998 movie "Patch Adams." In real life, he also gave back to St. Jude Children's Research Hospital.
In October 2013, Williams joined Jennifer Aniston,
"It's an honor to be a part of the St. Jude Children's Research Hospital family," Williams said in a statement at the time. "This year I appeared with Darcy in one of the St. Jude 'Thanks and Giving' television spots. Darcy and children like her from communities across America benefit from the lifesaving research and treatment being done every day at St. Jude. It means a lot to me to be involved."
Williams also helped with the
"His comedic genius was unparalleled & his philanthropic generosity unmatched. Thx for making the world a better place Robin Williams #RIP," Livestrong CEO Doug Ulman wrote in a Tweet.
Staff writers David Ng and Richard Verrier contributed to this report.