After a years-long battle with pancreatic cancer, Steve Jobs died on Wednesday at the age of 56.
Jobs reinvented the world's computing, music and mobile phone industries and changed the daily habits of millions around the globe.
Apple's website has been transformed into online memorial, a testament to the digital creativity that Jobs inspired.
"The world has lost a visionary. And there may be no greater tribute to Steve's success than the fact that much of the world learned of his passing on a device he invented," President Barack Obama said in a statement.
"For those of us lucky enough to get to work with him, it's been an insanely great honor," said Microsoft's Bill Gates, who once triumphed over Jobs but has seen his legendary status overtaken by the Apple co-founder in recent years.
Jobs stepped down as CEO in August and handed the reins to long-time operations chief Tim Cook.
"Apple has lost a visionary and creative genius, and the world has lost an amazing human being. Those of us who have been fortunate enough to know and work with Steve have lost a dear friend and an inspiring mentor. Steve leaves behind a company that only he could have built, and his spirit will forever be the foundation of Apple," said Apple CEO Tim Cook. "No words can adequately express our sadness at Steve?s death or our gratitude for the opportunity to work with him. We will honor his memory by dedicating ourselves to continuing the work he loved so much," he added.
"We are deeply saddened to announce that Steve Jobs passed away today.
Steve?s brilliance, passion and energy were the source of countless innovations that enrich and improve all of our lives. The world is immeasurably better because of Steve," Apple?s Board of Directors said in a statement.
Jobs was diagnosed of a rare form of pancreatic cancer in 2004, with the CEO asserting that the disease was treatable. But his health deteriorated rapidly over the past several years, and after two temporary leaves of absence he stepped down as chief executive and became Apple's chairman in August.