Zachary Uriah "Zack" Addy, Ph.D, is a fictional character in the television series Bones. He is portrayed by Eric Millegan. The character was introduced as Dr. Temperance Brennan's brilliant young assistant at the beginning of the series before he received his doctorate in Forensic Anthropology in Season 2. Millegan was a series regular for Seasons 1-3, appearing in all episodes.