Zachary Uriah Addy is a 27-year-old former child prodigy and yet already erudite. With an IQ over 163, he graduated college at 16, later joining the forensic team at the Jeffersonian as Dr. Brennan's Graduate Student. Zack is responsible and conscientious, the team's greatest stickler for rules. He does not guess!
He is inept socially and often has trouble conversing with people due to his "robotic" and always intellectual speech. Angela and Hodgins are seen often giving him advice and coaching him on social matters. He is also not skilled in the area of dating and relationships. His only on and off love interest being "Naomi in Paleontology", who hinted she was dissatisfied in his sexual prowess. He then turned to Booth for answers to his questions about sex and women, but was quickly turned down, as always, by Booth.
It is revealed later to his Jeffersonian colleagues he was a singer in his childhood; a result of his parents wanting to try to integrate him socially. This being a way to prove himself to Hodgins when Hodgins was doubting him. He also shares with Dr. Camille "Cam" Saroyan the fact he is "deceptively strong", his workout regimine being: 30 minutes on a treadmill, 100 sit ups, push ups, and leg lifts, and 20 minutes of free weights.
Under Dr. Brennan's tuition, he gained his doctorate and has published papers, at least one with Dr. Brennan. He has been working towards a second doctorate in Applied Engineering. He has a photographic memory and specializes in debriding( removing flesh from the bone).
He also eats Macaroni and Cheese for lunch....every day....
After gaining his Doctorate, he realised his job as Dr. Brennan's student was officially at an end. In an attempt to be taken seriously by Cam and to be able to effectively take the stand in cases, he asked Angela to give him a makeover. She reluctantly agreed, and he kept his job!
He comes from a large Lutheran family hailing from Michigan, one of 6 he has two brothers and three sisters. He has a friendly rivalry with 'boyish' colleague Dr. Jack Hodgins, the rebellious "bug-and-slime expert". Zack lives in the apartment above the garage at Dr Hodgins' home. He neither drives a car or rides a bike.
Zack was called on by the President of the United States to serve in the Iraq conflict in his areas of specialism. Zack made the decision to follow that calling and he spent 3 months in Iraq. He returned to the Jeffersonian having 'failed to assimilate' and after his army psychiatrist told him his presence was 'detrimental to a military team approach'. The true extent of the impact of his stint in the forces is unknown.
As Zack returned from Iraq, the Jeffersonian team began their involvement in the investigation of the Widow's Son serial killer case. They searched for guilty party whom they nickname "Gormogon" after finding various Gorgomon artefacts in a bank vault where the killer ate his victims.
Unknown at the time to the rest of the team, less than 9 months after his return from Iraq, Zack had been approached by a man known as 'The Master', and Zack ended up helping The Master in his cause to rid the world, through murder and canniblism of those in Secret Societies. Zach falsified evidence, hampering the investigation.
Zack rigged an explosion to act as a diversion in an attempt to help The Master retrieve his most valued possession from the Jeffersonian. The diversion did not go according to plan and while delaying the explosion to save Hodgins from unecessary injury, Zack harmed himself more than he had planned to sacrifice and may well lose use of both his hands.The extent of how involved he was in the actual murders and cannabilisation of the victims is unclear as Zack changed his story but it seems he did not murder or eat anyone.
Why, and how Zack became involved with the Master is unclear. But his tenure in the Jeffersonian team is at an end.