Kevin Mitnick, a reformed hacker who was once one of the FBI’s “most wanted” cybercriminals, has died at the age of 59.

Mitnick spent five years in prison for computer and wire fraud following a two-year federal manhunt in the 1990s.

But after his release in 2000 he reinvented himself, becoming a renowned “white hat” hacker, cybersecurity consultant and author.

He died on Sunday following a 14-month long battle with pancreatic cancer.

“Kevin was an original; much of his life reads like a fiction story,” his obituary reads.

“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.”

In the 1990s, Mitnick gained notoriety breaking into government websites and corporate networks, including Pacific Bell, and stole corporate data and credit card information.

He was involved in the theft of thousands of credit card numbers and data files across the country in addition to working his way to into the country’s cell networks, vandalizing corporate, government and university computer systems.

He was dubbed as the “most wanted” computer hacker in the world by investigators.

A two-year-long nationwide FBI manhunt led to his 1995 arrest and he eventually pleaded guilty to computer and wire fraud.

Authorities believed he had access to corporate trade secrets worth millions of dollars.

In his 2011 memoir, Ghost in the Wires, Mitnick denied using his skills to steal or exploit information for financial gain.

“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,” he wrote.

His arrest sparked a ‘Free Kevin’ movement in the hacking community, which lobbied on his behalf, including with rallies outside the prison where he was held.

Following his release from prison, he became a “white hat” hacker, writer and public speaker.

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.

“Kevin will always remain ‘the world’s most famous hacker’ and was renowned for his intelligence, humor and extraordinary skill with technology, surpassed only by his talent as the original ‘social engineer,’” the company said in a statement on Thursday.