US prosecutor Jane Robison said Stuart Dunn entered his plea in Los Angeles and was also ordered to complete six months of residential rehab and placed on five years of felony probation.
Dunn has repeatedly been arrested in his pursuit of Kunis.
In February, he was arrested for breaking into her vacant condominium, and authorities arrested him again in May, after he waited for her outside her gym for three days.
Superior Court Judge George Lomeli also gave Dunn credit for 528 days he spent in jail.
Dunn was also ordered to stay away from Kunis' agents, managers and assistants.