Mitnick vandalised corporate, government, university computer systems and mobile phone networks.
His work prompted a two-year FBI manhunt which eventually led to his arrest in 1995. He later pleaded guilty to computer and wire fraud and was jailed for five years.
Kevin Mitnick outside court in 2000 (Photo: Getty)
At the time, Mitnick was dubbed as the "most wanted" computer hacker in the world by investigators and authorities in Washington believed he had access to corporate trade secrets worth millions of dollars.
US authorities accused him of causing millions of dollars in damages to companies including Motorola, Novell, Nokia and Sun Microsystems.
During his time in prison, Mitnick was reportedly placed in solitary confinement for nine months because officials were worried that he could emulate a modem by whistling into a payphone and “hack NORAD and trigger a ballistic missile” causing a nuclear war.
His arrest caused a movement in the hacking community to start, known as 'Free Kevin'.
Speaking at the time of his release in 2000, Mitnick said he only committed “simple crimes of trespass.”
Mitnick added: “I wanted to know as much as I could find out about how phone networks worked.
“My hacking activity actually was a quest for knowledge, the intellectual challenge, the thrill and the escape from reality.”
Kevin Mitnick being released from prison in 2000 (Photo: Getty)
Following his release from prison, he became a "white hat" hacker and a famed author. A "white hat" hacker aims to use their skills and identify vulnerabilities or security issues of organisations to test security configurations.
In 2003, he founded Mitnick Security Consulting, which advised Fortune 500 companies and government agencies on cybersecurity.
In 2011, he became "chief hacking officer" and part owner of KnowBe4, which offers phishing security awareness training.
In his 2011 memoir, Ghost in the Wires, Mitnick later denied using his skills to steal or exploit information for financial gain.
He wrote: "Anyone who loves to play chess knows that it's enough to defeat your opponent. You don't have to loot his kingdom or seize his assets to make it worthwhile.”
His obituary said: “Kevin was an original; much of his life reads like a fiction story.
"He grew up brilliant and restless in the San Fernando Valley in California, an only child with a penchant for mischief, a defiant attitude toward authority, and a love for magic."
Stu Sjouwerman, a close friend and business partner at KnowBe4, said: "Kevin was a dear friend to me and many of us here at KnowBe4.
“He is truly a luminary in the development of the cybersecurity industry, but mostly, Kevin was just a wonderful human being and he will be dearly missed."
A memorial for Mitnick will take place in Las Vegas in August and he will be buried near his mother and grandmother in a local Jewish cemetery.
