Chaney, of Jacksonville, Florida, pleaded guilty to nine felony counts, including wiretapping and unauthorised access to a computer.
Scarlett, Christina Aguilera and Mila Kunis all agreed to waive protection of their identity to raise awareness of internet hacking.
He was arrested last year as part of a year-long investigation dubbed Operation Hackerazzi and jailed by US District Judge S James Otero in LA.
"It's hard to fathom the mindset of a person who would accomplish all of this," the judge said. "These types of crimes are as pernicious and serious as physical stalking."