Mitnick, 36, may be free, but he will not be able to use a computer for another three years without the permission of his probation officer.
The conditions of his parole will undoubtedly hamper his ability to find gainful employment, as most companies and organizations require computer use. The convicted hacker also will have to forgo email and reach friends and family members the old-fashioned way: through a land-line telephone.
In a lengthy statement read to a gathering of reporters in front of the prison, Mitnick lambasted the prosecutors who brought him to trial and New York Times reporter John Markoff for his coverage of the case.
"My actions and my life have been manipulated and grossly misrepresented by the media since I was 17," he said in his statement, which can be found on the "Free Kevin" Web site. "My case is a case of curiosity--I wanted to know as much as I could find out about how phone networks worked and the 'ins' and 'outs' of computer security. There is no evidence in this case whatsoever, and certainly no intent on my part at any time, to defraud anyone of anything."
Law enforcement officers and counselors have described Mitnick as a loner who found a sense of power through his computer.
His obsession with breaking into computer systems and either stealing company files or tinkering with software as pranks began when he was a teen-ager growing up in the Los Angeles area, according to assistant U.S. Attorney Christopher Painter, who prosecuted Mitnick in 1995.
His first brush with the law came in 1981, when as a 17-year-old he was arrested for stealing computer manuals from Pacific Bell's switching center in Los Angeles. He was prosecuted as a juvenile and sentenced to probation, Painter said.
A year later he was caught breaking into computers at the University of Southern California and was jailed for six months.
He was caught several other times, and after an arrest in 1988 on similar hacking charges, his lawyer convinced a judge that Mitnick's problem was similar to a drug or gambling addiction. He served one year at a low-security federal prison in Lompoc, and after his release, he underwent treatment similar to the 12-step Alcoholics Anonymous model, Painter said.
Later, Mitnick violated the conditions of his parole and had a warrant issued for his arrest. He went underground in 1992.
For nearly three years, FBI agents suspected Mitnick of attacking systems belonging to software makers, ISPs and educational institutions including Netcom, Colorado Supernet, Motorola, Nokia, Fujistu, Novell, NEC, Sun Microsystems and USC.
He eluded authorities until 1995, when he hacked into the computer files belonging to Tsutomu Shimomura, a researcher at the federally financed San Diego Supercomputer Center.
Two months after the hack, Shimomura, a skilled computer security expert, tracked down Mitnick in Raleigh, N.C.
Mitnick was arrested in February 1995 and held without bail. He served nearly four years in the Metropolitan Detention Center in Los Angeles while awaiting trial in federal court. He pleaded guilty March 26 to seven counts of wire fraud, computer fraud and illegal interception of a wire communication.
Mitnick was then sentenced to six months at the medium-security federal prison in Lompoc, where he worked as a groundskeeper while serving his term.
His arrest and conviction was cause for celebration for Shimomura and federal authorities, but many followers came to Mitnick's defense--even setting up a "Free Kevin" Web site.
Instead of serving as a deterrent, Mitnick's arrest may have sparked a new breed of hackers, said Mitnick's court-appointed attorney, Donald C. Randolph, of Santa Monica, Calif.
"I'm afraid it has had exactly the opposite effect," Randolph said. "The government didn't distinguish between computer prankster and computer terrorist in prosecuting Kevin Mitnick. The distinction is appreciated by the upcoming 20-something generation who perfectly understand the difference."
Randolph criticized federal authorities for exaggerating Mitnick's prowess. "He never deprived owners of their unfettered use of their computers," he said of his client. "He just peeked at it. Prosecutors couldn't admit they were pursuing a peeker; they had to go after the myth they created."
Painter, the assistant U.S. attorney who prosecuted the case, countered that Mitnick was much more than someone who simply "peeked" at other people's files.
"We didn't prosecute this case with the goal of making Mitnick an example," Painter said. "His conduct warranted it. He was one of the most prolific computer hackers, and for two and a half years he was on a virtual hacking spree against a whole panoply of enemies."
Shimomura and the Times' Markoff later co-authored a book about Mitnick titled "Takedown: The Pursuit and Capture of America's Most Wanted Computer Outlaw."