Andrew Auernheimer is scheduled to appear in federal court in Newark on Monday.
The former Arkansas resident was convicted in November of identity theft and conspiracy to gain unauthorized access to computers. Prosecutors are seeking a sentence of 33 to 41 months. Auernheimer's attorney says his client should receive probation.
Prosecutors say Auernheimer was part of an online group that tricked AT&T's website into divulging the email addresses, including those of New York Mayor Michael Bloomberg, film mogul Harvey Weinstein and other celebrities.
The group then shared the addresses with the website Gawker, which published them in redacted form.
A second defendant pleaded guilty in 2011.