After his release he will also have to pay $605,000 in restitution and perform 1,000 hours of community service.
Kretsinger initially denied any involvement in the breach, but has subsequently pleaded guilty to the charges of conspiracy and unauthorized impairment of a protected computer raised against him.
As a reminder: he admitted to having used proxy services from hidemyass.com to (unsuccessfully) hide his online activities, then having probed with other LulzSec members into Sony's computer systems looking for vulnerabilities. An SQL injection attack allowed them to breach the system.
Kretsinger pleaded guilty a month after it was reveled that LulzSec leader "Sabu" had been working with law enforcement to secure evidence against the group's other members.
According to Reuters, the prosecutors have refused to comment on whether Kretsinger has also cooperated with law enforcement in order to get a reduced sentence.
20-year-old Raynaldo Rivera (aka "neuron") - Kretsinger's partner in this particular crime - has also pleaded guilty to the charges and will be sentenced in the upcoming days.