Christopher Chaney has been indicted in California on 26 counts, including wiretapping, and faces up to 121 years in prison if convicted.
Federal prosecutors say Chaney hacked into email accounts belonging to Aguilera, Johansson and Mila Kunis. Some nude photos taken by Johansson herself were posted on the Internet.
Authorities say they 35-year-old offered some material to celebrity blog sites but there isn't any evidence that he profited from his scheme.
Chaney, who is free on $10,000 bond, has apologized for his actions.