Called "The Coach" because he advised tech's biggest executives, Campbell was arguably the most influential man -- and one of the most beloved -- in Silicon Valley.
Bill Campbell -- mentor to Apple CEO Steve Jobs, Google co-founder Larry Page, Facebook founder Mark Zuckerberg and Twitter CEO Jack Dorsey -- has died. He was 75.
"Bill Campbell passed peacefully in his sleep after a long battle with cancer," his family said in a statement on Monday. "The family appreciates all the love and support but asks for privacy at this time."
Word of his passing has drawn tributes from notable tech executives and companies, who remembered the man many called simply "Coach."
"Bill Campbell was a coach and mentor to many of us at Apple, and a member of our family for decades as an executive, advisor and ultimately a member of our board," Apple said in a statement. "He believed in Apple when few people did and his contributions to our company, through good times and bad, cannot be overstated. We will miss his wisdom, his friendship, his humor and his love for life."
From 1974 to 1979, Campbell really was head coach of Columbia University's football team, the Columbia Lions. He earned his nickname, however, helping Silicon Valley's entrepreneurs become industry leaders. During more than 30 years in California's tech center, 30 miles south of San Francisco, executives valued his plain-speaking, down-to-earth advice. "He loves people, and he loves growing people," Apple's Jobs told Fortune in 2008.
Campbell was one of the first directors appointed to Apple's board in 1997, when Jobs returned to the company he co-founded. Campbell served on the board until 2014, making him the longest-serving board member in Apple's history.
"When Bill joined Apple's board, the company was on the brink of collapse," Apple CEO Tim Cook said in a statement when the company announced Campbell's retiring. "He not only helped Apple survive, but he's led us to a level of success that was simply unimaginable back in 1997."
In 2001, noted venture capitalist John Doerr, of Kleiner Perkins Caufield & Byers, asked Campbell to mentor Google's newly named CEO, Eric Schmidt. He helped Schmidt build the company's executive team.
"Bill Campbell, our very close friend, died this morning," Schmidt wrote Monday on his Facebook page. "A man with a huge heart, who hugged everyone he met with, was more than a mentor. He helped us build Google and in countless ways made our success possible.... His legacy is the smile that he created on everyones face, and the great leaders of the valley whom he coached. Bill was a truly gifted man, and the world lost a great leader this morning."
Campbell's coaching style, according to those who knew him, typically started by asking execs wanted they wanted to fix and digging into how they ran staff meetings. He also made sure members of the management team could play well with others, as well as encourage innovative thinking.
"I'm not innovative. I support innovation," Campbell said in a rare interview in 2007 with the McKinsey Quarterly. "There's not a product idea that I'll ever have that's going to amount to anything. But what I'll do is make sure that the right people are in the room and that the lunatic fringe has an opportunity to contribute."
Doerr on Monday said Silicon Valley has "lost a giant."
"Bill was our SuperCoach - colorful confidante and mentor for leaders and whole teams - from Intuit to Apple, Amazon, Go, Google and more," Doerr said. "Bill's greatest joy was coaching youth at Sacred Heart. His legacy will live forever in the hearts of teams striving for excellence."
Many described Campbell as a friend, including Ben Horowitz, co-founder of venture capital firm Andreessen Horowitz. "Whenever I struggled with life, Bill was the person that I called," Horowitz wrote in a tribute. "I didn't call him, because he would have the answer to some impossible question. I called him, because he would understand what I was feeling 100%. He would understand me."
"Will greatly miss friend and mentor Bill Campbell. Coach," AOL's Tim Armstrong wrote on Twitter.
Dick Costolo, former CEO of Twitter, also commented about the "horrible" news of Campbell's passing. "Called me on my last day at Twitter & had both the funniest & most insightful comments," he wrote in a tweet.
CNET's Richard Nieva and Shara Tibken contributed to this report.