Svartholm Warg was convicted by the Nacka District Court after a hacking attack against Swedish IT firm Logica through which he gained unauthorized access to the personal data of thousands of people, which he then published on the net.
The conviction was also for hacking into the mainframe of Nordea, Scandinavia's biggest bank. The Swede maintained his innocence throughout the trial, claiming that someone else had used his computer remotely.
The data breach at Logica, which supplies public agencies in Sweden with personal data from the country's population registry, was discovered over a year ago, and the 28-year-old Svartholm Warg was believed to have stolen the information of 20,000 police employees, as well as millions of personal identity numbers (personnummer).
The Pirate Bay founder and an accomplice was also suspected of having copied a registry with nearly 11,000 names of people with protected identities and posting the data online.
Svartholm Warg's accomplice, a 36-year-old man living in Dalarna, central Sweden, was also convicted for data breaches, and must also seek psychiatric care and drug rehabilitation, the court ruled.