Dr. Zack Addy (Seasons 1–3; recurring afterward) is introduced as Dr. Brennan's graduate student and assistant at the Jeffersonian Institute at the start of the series.
In the second season, he receives his doctorate in forensic anthropology and applied engineering and becomes a professional forensic anthropologist. Zack is closer to the stereotypical geek than anyone else on the team.
Although well–meaning, helpful and friendly, when a situation calls for social interaction or intuition, he is often lost. During the course of events leading up to the death of Howard Epps, Zack was nearly killed after he unwittingly triggered a pressure sensor tied to a bomb affixed to the headless body of Caroline Epps.
He is extremely intelligent—in episode 11 it is said his IQ is significantly above 163 (which is already a genius level). He is also Hodgins' best friend, and lives in the upper part of Hodgins' garage. At the end of Season 3, he was revealed to be an accomplice to "Gormogon". He was admitted to a psychiatric institution following his confession to murdering the Lobbyist ("The Knight on the Grid").
While in the psychiatric institute, Zack was regularly visited by Hodgins and Dr. Sweets. Some time later, Zack broke out of the psychiatric ward in order to help his friends solve a case. After the case was solved, Zack willingly returned to the psychiatric facility.
Zack later told Sweets that he did not kill anyone, but told Gormogon where the victim was in order to murder and cannibalize them. Sweets wanted to tell the others, but Zack told him not to do so to avoid being sent to a "regular jail" as he "would not do well in prison".
Full Name: Zachary Uriah Addy
Nickname(s): Zack; Zackaroni; King of the lab
Religion: Atheist, raised Lutheran
Status(presumed): Inmate
Occupation: Forensic anthropologist
Affiliation: Jeffersonian Institute
Title: Doctor (PhD)
Physical Description Gender: Male Hair Colour: Brown Eye Colour: Brown
Portrayed by: Eric Millegan
First Appearance: Pilot Last Appearance: regular: The Pain in the Heart The Parts in the Sum of the Whole