After several years of failing health and medical leaves of absence, Steve Jobs today announced he would resign as CEO of Apple.
"I have always said if there ever came a day when I could no longer meet my duties and expectations as Apple's CEO, I would be the first to let you know," Jobs, 56, wrote in his letter of resignation "to the Apple board of directors and the Apple community." "Unfortunately, that day has come.
"I would like to serve, if the Board sees fit, as Chairman of the Board, director and Apple employee," Jobs added. "As far as my successor goes, I strongly recommend that we execute our succession plan and name Tim Cook as CEO of Apple."
In a separate release, Apple said that Cook, 50, was, in fact, named CEO, Jobs was elected chairman of the board and Cook was added to the company's board.
"Steve's extraordinary vision and leadership saved Apple and guided it to its position as the world's most innovative and valuable technology company," said Art Levinson, chairman of Genentech, on behalf of Apple's board. "Steve has made countless contributions to Apple's success, and he has attracted and inspired Apple's immensely creative employees and world class executive team. In his new role as chairman of the board, Steve will continue to serve Apple with his unique insights, creativity and inspiration."
Apple declined to comment on the current state of Jobs' health, or make any comment beyond the written statements.
Since 2004, Jobs has battled a rare form of pancreatic cancer, had a liver transplant in 2009, and taken three leaves of absence from Apple, the most recent of which was earlier this year.
Jobs and Apple have faced criticism for releasing so little official information about his medical condition considering his iconic identification with the Apple brand.
But because of his illnesses, Apple has been putting in place contingency plans, an analyst said.
"The board has been preparing for this eventuality," said Michael Gartenberg, research director of Gartner IT analysts. "Mr.. Cook has shown remarkable leadership in the two times that he has taken the reins when Jobs was out on medical leave. And there is no reason to think he simply won't continue that pattern of excellence."
In June, Jobs got a standing ovation at a software developers' conference in San Francisco to introduce Apple's Lion operating system and a wireless service called iCloud. After so much uncertainty about his health, his mere presence at the event dwarfed the announcement itself.
"We love you," shouted someone in the crowd.
"I appreciate it very much," Jobs answered.
People emailing or tweeting from the conference said he looked gaunt, however.
Jobs "looks extremely thin," ABC News correspondent Neal Karlinsky wrote in an email from the audience, but added, "He's walking steadily and seems to have energy."
Macrumorslive.com, a website that covers Apple full-time, commented, "Steve sounds... exasperated. Weirdly quiet and not as energetic."
Jobs didn't stay long, commanding the stage for approximately 3 minutes.
"Today, we're going to talk about software," he said, before handing off to Phil Schiller, Apple's senior vice president for worldwide marketing.
Jobs returned to the stage to introduce iCloud, a service he said would make it possible for users to access photos, music, documents and other content at any time from any device.
He demonstrated how photos taken with an iPhone were visible on a user's iPad moments later.
Immediate reaction to the new offerings was positive, but many in the crowd of 5,200 were still reacting to Jobs himself, who wore a trademark black mock turtleneck and blue jeans.
The June event was his second public appearance since his most recent medical leave. The other, in March, was for the release of the company's successful iPad 2 tablet.
Jobs concluded his resignation letter with a look toward Apple's future with Cook as CEO.
"I believe Apple's brightest and most innovative days are ahead of it. And I look forward to watching and contributing to its success in a new role," he wrote. "I have made some of the best friends of my life at Apple, and I thank you all for the many years of being able to work alongside you."
ABC News' Neal Karlinsky contributed to this report.