Los Angeles District Attorney's spokeswoman Jane Robison says Jeffrey Jones entered the plea Tuesday to a felony charge of failing to update his registry information in June.
Jones' registration was required because he pleaded no contest in 2003 to employing a 14-year-old boy to pose for sexually explicit photos.
The 64-year-old actor is also required to perform 250 hours of community service. His sentence was first reported by celebrity website TMZ.com
Jones has also appeared in "Beetlejuice" and other films.