LOS ANGELES - In public, Robin Williams shared only the joy he found in life, never the sorrow. He was the same man in private, shielding even longtime friends from the darkness of depression that finally enveloped him.
"I can honestly say I never saw him in the down times," said comedian David Steinberg, who was friends with Williams for more than 30 years and toured with him for six months last year in a two-man show. "I read about it, heard about it, but that down time he kept to himself."
When the endlessly inventive, explosively manic comedian and actor was found dead in his Northern California home Monday, an apparent suicide, the brutal shock was felt by fans, friends and colleagues alike.
Williams, 63, who had been so breezily open about seeking therapy - "I went to rehab in wine country to keep my options open," he joked in 2006 - minimized or hid the immensity of his pain from perhaps all but a handful of people.
Steve Martin, a pal who worked with Williams, tweeted that he was "stunned by the loss." Chevy Chase, in a statement, said he and friend Williams both suffered from depression but added, "I never could have expected this ending to his life."
Last month, the star of "Mrs. Doubtfire," "Good Will Hunting" and "Good Morning, Vietnam" said he was re-entering a 12-step program after months of nonstop work. After he died, his publicist confirmed he had suffered in recent weeks from depression.
It was one of several efforts over the years to overcome substance abuse. Solace from those close to him was a different matter - even as Williams faced self-described financial pressures.
Comedy club impresario Jamie Masada said he nicknamed Williams the "Doctor of Soul" because his irresistible humor could make people forget their problems. How Williams coped with his own woes, or that he had any, remained a mystery, Masada said.
"Robin always had this mask on. I could never tell that he was depressed. He had such high energy, always," said the owner of the famed Laugh Factory clubs.
Williams was in fine form last year during his U.S. concert tour with Steinberg, in which Steinberg served as interviewer and partner-in-laughs for his friend. Their venture stemmed from a benefit the pair had done for the Cleveland Clinic.
"He seemed a little mellower," said Steinberg, adding that there was never any drug or alcohol use by Williams during the tour which, while grueling, was a success.
Cinematographer John Bailey, who worked with Williams on the independent film "The Angriest Man in Brooklyn" in 2012, said the role he played, of a difficult, terminally ill man, was revealing.
It "gets to that sort of really dark humor that he had, which is just below the surface. In this film it's right there. People didn't really understand it. They didn't want to accept that part. It's a significant part of his genius."
Whatever distress he was feeling, Williams was invariably charming and professional, whether working for pay or charity, others said.
On the set of his 2013-14 CBS comedy, "The Crazy Ones," Williams' favorite word was "wonderful!" said series executive producer Dean Lorey, who also recalled his kindness toward Lorey's 16-year-old son on set.
"I remember seeing the two of them chatting together and thought, 'Gotta remember this moment,'" Lorey said in an email exchange. "Robin would talk to anyone, in a very genuine way, and he always made them feel special."
In a September 2013 interview with Parade magazine, Williams said money was part of the reason for his rare return to a TV sitcom.
"There are bills to pay. My life has downsized, in a good way. I'm selling the ranch up in Napa. I just can't afford it anymore," Williams told Parade, adding that his two divorces hadn't cost him everything but that he'd "lost enough. Divorce is expensive."
Mara Buxbaum, Williams' publicist, said Wednesday he had "zero" financial difficulties.
The series' fate hung over Williams when he and Steinberg last spoke a couple months ago. Williams was waiting anxiously to hear whether the freshman show would be renewed for the 2014-15 season. It was canceled.
"It mattered to him," Steinberg said.
But Williams thought of others first. He gave and gave, of his immense talent, his friendship and more, and in ways both big and small. It wasn't just high-profile generosity, such as his efforts for Comic Relief and U.S. military and veterans, his friends said.
"He was one of those who just wasn't a taker. He was about looking after people," said Steinberg. "I wish that extended to himself."
Masada recalled a fundraiser he, Williams and comedian Paul Rodriguez held for a Los Angeles high school to help equip its football team. The benefit left the trio drenched in sweat because the school auditorium was stifling hot.
"A couple days later I got a call from the principal of the school, telling me that Robin Williams came back, brought a contractor to put in air conditioning for nothing and didn't want anybody to know about it," Masada said.
Gilbert Gottfried was another recipient of Williams' thoughtfulness. It was years ago in New York, when Gottfried was an up-and-coming comedian about to take the stage at the Improv in Times Square and Williams walked in. The club moved to bump Gottfried, but Williams demurred.
"He said, 'I have people in the audience and I'd really like them to see Gilbert tonight,'" Gottfried recalled. Williams was just as warm when they ran into each a few years ago in NY, inviting him to a restaurant with Billy Crystal.
When they said goodbye, Williams mentioned he was off to rehab.
"So we hugged, and he just walked off and disappeared in the darkness," Gottfried said.