The 56-year-old cancer survivor will present Apple's new operating system, dubbed "Lion," at a developers conference in San Francisco on June 6.
Jobs went on leave in January, his third medical absence since 2004, but has retained his title of chief executive at Apple.
He underwent an operation for pancreatic cancer in 2004 and received a liver transplant in 2009, but Apple has not released any details about his latest health issues.
"Lion" will be the eighth major iteration of Apple's operating system for the California company's increasingly popular Macintosh computers.
Apple stock price finished the trading day up more than three percent to ê347.83 after the morning announcement that the culture-changing company's renowned pitchman will play a starring role at the event.
"If Steve Jobs is going to be there, it means something is going to launch," said analyst Rob Enderle of Enderle Group in Silicon Valley.
Apple's rare decision to disclose what Jobs and other executives will discuss could be intended to curb the rampant speculation that routinely precedes the company's events, according to Gartner analyst Michael Gartenberg.
"The key is to remember it is a developers conference," Gartenberg said. "They could be talking up software so people don't expect to see an iPhone 5 or a new Macbook."
Apple promised that announcements would include an "iCloud services offering," which many expected to include a streaming music. Apple provided no details.
Google and Amazon.com recently launched services that let people store digital music in online "lockers" and then listen to tunes on any Internet-linked devices.
Given Apple's success with selling music at its online iTunes shop and its relationship with record labels, a "cloud" service playing into those strengths makes sense, according to Gartenberg.
"If they are going to introduce a new cloud-based service, it feels right that it would have something to do with music," Gartenberg said.
"We are going to see something much more than just another music locker like Google introduced and like Amazon introduced," the analyst continued. "Apple would not be getting into a cloud service if all it had was a 'me too' offering."
Online services and software platforms are vital underpinnings to the success of gadgets, even hot-selling iPhones and iPads.
Apple might also use the opening of the conference to announce a switch away from Intel chips in its laptop line, Enderle theorized.
Intel on Tuesday introduced new "Ultrabooks" that the US chip giant billed as a lean new kind of computer that combines the strengths of tablets and laptops in a single machine.
Asus is expected to have the first "Ultrabook" built with Intel chips available by the end of the year at a price less than ê1,000.
Jobs may be faced with deciding whether to embrace Intel technology powering iPad rivals or to take a more defensive posture by shifting to non-Intel chips at the heart of Apple's leading line of tablet computers.
"With Intel building tablet devices with keyboards, Steve Jobs will be between a rock and a hard place," Enderle said.
"But if anyone can get out of that, it's him," the analyst continued. "He is a master chessman. Intel has made a move and now it is up to him."
Enderle didn't dismiss the chance that Apple might provide developers an early peak at the next-generation iPhone.
"We are all going to be very attentive as he gets on stage and announces that one more thing," Enderle said in reference to the trademark line Steve Jobs uses to end presentations with major surprises.