Mitnick died on Sunday in Las Vegas after a 14-month battle with pancreatic cancer, said Stu Sjouwerman, CEO of the security training firm KnowBe4, where Mitnick was chief hacking officer.
His colourful career - from student tinkerer to FBI-hunted fugitive, imprisoned felon and finally respected cybersecurity professional, public speaker and author tapped for advice by US politicians and global corporations - mirrors the evolution of society's grasp of the nuances of computer hacking.
Through Mitnick's professional trajectory, and what many consider the misplaced prosecutorial zeal that put him behind bars for nearly five years until 2000, the public has learned how to better distinguish serious computer crime from the mischievous troublemaking of youths hell-bent on proving their hacking prowess.
"He never hacked for money," said Sjouwerman, who became Mitnick's business partner in 2011.
Much fanfare accompanied Mitnick's high-profile arrest in 1995, three years after he had skipped probation on a previous computer break-in charge.
The US government accused him of causing millions of dollars in damages to companies including Motorola, Novell, Nokia and Sun Microsystems by stealing software and altering computer code.
But federal prosecutors had difficulty gathering evidence of major crimes and, after being jailed for nearly four years, Mitnick reached a plea agreement in 1999 that credited him for time served.
Upon his January 2000 release from prison, Mitnick told reporters his "were simple crimes of trespass".
He was initially barred for three years from using computers, modems, mobile phones or anything else that could give him internet access - and from public speaking.
Those requirements were gradually eased but he was not allowed back online until December 2002.
Mitnick would impersonate company employees to obtain passwords and data, a technique known as pretexting that remains among the most effective in hacking and which typically requires considerable research to pull off successfully.
"His ingenuity challenged systems, incited dialogues and pushed boundaries in cybersecurity. He will remain a testament to the uncharted power of curiosity," tweeted Chris Wysopal, who as a member of the white-hat hacking group L0pht testified before the US Senate a few years before Mitnick did the same.
"My hacking activity actually was a quest for knowledge, the intellectual challenge, the thrill and the escape from reality," Mitnick said during a March 2000 congressional hearing.
Mitnick had first been arrested for computer crimes at age 17 for brazenly walking into a Pacific Bell office and taking a handful of computer manuals and codes to digital door locks.
He served a year in a rehabilitation centre, deemed by a federal judge as being addicted to computer tampering.
Mitnick had been raised in the bleak Los Angeles suburb of Panorama City by his mother, who divorced his father when he was three.
An overweight, lonely teenager, he dropped out of high school and found friends only when he stumbled into the world of phone phreaks - teens who used stolen phone codes to make free long-distance calls.
Enthralled by the possibility of using computers to gain access and power, Mitnick began breaking into voice mail and computer systems, rifling through private files and taunting those who crossed him.
But another side of Mitnick became clear in his conversations with journalist Jonathan Littman printed in in the book The Fugitive Game: Online with Kevin Mitnick.
Although a computer file containing 20,000 credit card numbers copied from the internet service provider Netcom was found on Mitnick's computer after a 1994 arrest, there is no evidence he ever used any of the accounts.
In addition to his work at KnowBe4, where Mitnick was not involved in day-to-day operations, he ran a separate penetration-testing business with his wife, the former Kimberley Barry.
She is a native of Australia, where the two met.
