The two built and marketed the first personal computer to generate color graphics, the Apple II. Jobs would go on to become the showman and the mastermind behind revolutionary products such as the iPod, iPhone and iPad.
Although the two didn't stay as close through the decades, they remained in touch.
Wozniak was among millions mourning Jobs' death on Wednesday at 56.
"We've lost something we won't get back," Wozniak said in a phone interview with The Associated Press. "The way I see it, though, the way people love products he put so much into creating means he brought a lot of life to the world."
Wozniak wiped away tears in a separate AP video interview.
Jobs "gets a reputation for being a strong leader and for being brash. But to me he was always so kind, such a good friend," he said.
Wozniak, five years older than Jobs, first met him when Jobs was still in high school. Early on, the two experimented with technology in a mischievous way: by building so-called "blue boxes" that emits tones at the right frequencies to trick phones into allowing users to make free calls anywhere in the world.
The two were also active in the Homebrew Computer Club, a group of computer hobbyists, where Wozniak's homemade computer drew attention from other enthusiasts. That computer piqued Jobs' interest as something with potential far beyond the geeky hobbyists of the time.
The pair started Apple Computer Inc. in the garage of Jobs' parents in 1976 (a rarely-mentioned third co-founder, Ronald Wayne, left shortly after its creation). According to Wozniak, Jobs suggested the name after visiting an "apple orchard" that Wozniak said was actually a commune.
Wozniak and Jobs both left Apple in 1985. In Jobs' case, it followed a clash with then-CEO John Sculley. Jobs resigned his post as chairman of the board and left Apple after being pushed out of his role leading the Macintosh team.
Jobs returned in 1997 as interim CEO after Apple, then in dire financial dire straits, bought Next, a computer company he started. This was the start of Apple's amazing upswing, which continues today with the popularity of products such as the iPhone and the iPad.
In recent years, they weren't as close — Jobs declined to write the forward for Wozniak's autobiography, iWoz, which was released in 2006.Wozniak said he last saw Jobs about three months ago, shortly after Jobs briefly emerged from a medical leave to unveil the company's latest iOS mobile software and its iCloud content syncing service.
Wozniak said Jobs looked ill and sounded weak at the time.
Jobs, whose cause of death wasn't revealed by Apple or his family, had battled cancer in 2004 and underwent a liver transplant in 2009 after taking a leave of absence for unspecified health problems. He took another leave in January — his third since his health problems began — and officially resigned as CEO in August. Jobs became Apple's chairman and handed the helm to his hand-picked successor, Tim Cook.
His death was followed by an outpouring of grief around the world from Apple fans and competitors, as well as heads of state. In a sign of how pervasive the gadgets he spearheaded have become, much of the mourning was done on Apple gadgets: People held up pictures of candles on their iPads, reviewed his life on Macintosh computers and tapped out tributes on iPhones.
Wozniak, 61, said Jobs was a good husband and father and a great businessman who had an eye for details. He said Jobs was a good marketer and understood the benefits of technology.
When it came to Apple's products, "while everyone else was fumbling around trying to find the formula, he had the better instincts," he said.
According to Wozniak, Jobs told him around the time he left Apple in 1985 that he had a feeling he would die before the age of 40. Because of that, "a lot of his life was focused on trying to get things done quickly," Wozniak said.
"I think what made Apple products special was very much one person, but he left a legacy," he said. Because of this, Wozniak hopes the company can continue to be successful despite Jobs' death.