Will's mother, Mary Anne Zimmerman, was killed by a Giant Lizard Creature in 1985 in front of Will's eyes when he was 8-years-old. Everyone Will talked to thought he was crazy because he told people a monster killed his mother. Eventually, Will convinced himself that the monster he saw wasn't real and became obsessed with perception, he even published several papers on how easily the human mind can perceive an illusion as reality.
He was acknowledged as a good man with an excellent talent for psychiatry and analysis. But, his inability to adjust to the status quo of investigating crimes has resulted in him losing his FBI job, and he then began working as a consultant for the homicide department of the OCPD. While working for the department, Will's co-workers mocked Will by calling him "Sherlock Holmes" as he had the habit of thinking too far outside the box and over analyzing things, refusing to accept the simplicity of some cases.
After being recruited by Magnus in her work at the Old City Sanctuary, Will discovers a new and strange world that is both unbelievable yet completely plausible to him. While his ideas have put him ahead of his time, he finds the world of "abnormals" to be fantastical in a way he can ultimately understand.
Although Will was less than comfortable at first, he has proven himself invaluable in gaining the confidence of his first patient, an Abnormal child named Alexei. This only serves to prove that Magnus was right about his instinct and genuine thirst to know the truth. And she knows that he will prove invaluable to the Sanctuary. He has also totally proven himself to Ashley Magnus after helping to rescue her from what could have been her death.
His choice to stay at the Old City Sanctuary is made after a conversation with Dr. Magnus when she reveals her deepest secrets to him. He asks this of Magnus because of the fact that he has been thrust into a world that he repressed as a child and explains to him how she was there the day an Abnormal killed his mother. Even after learning this fact, Will still decides to work for Magnus as Will can see past the monstrous appearances of some abnormals in order to see how desperately some abnormals need their help.
Despite being involved in the Sanctuary Network for a relatively short time, Will's status as Magnus' protégé seems to give him additional prestige within the Network, with some people suggesting that Magnus is grooming him to take charge of the Sanctuary Network. This is confirmed later by Magnus when she admits that one day Will may have to lead the Sanctuary without her, suggesting that in her absence, Will is the next-in-line to take over her position. This is further confirmed later when the Heads of House for all the Sanctuary facilities worldwide unanimously decide to appoint Will as the acting Head of the Global Sanctuary Network in the face of Magnus' disappearance. Upon Magnus' return Will gladly transfers control of the Global Network back to her.
As Magnus' second-in-command, Will has knowledge of all aspects of the Sanctuary Network as well as access to all of Magnus' contacts and resources. Nikola Tesla exploits this aspect when he uses a clause in the Sanctuary Charter to temporarily depose Magnus as the Head of the Old City Sanctuary on the grounds of (Magnus') ill health when Magnus refuses to cooperate with Adam Worth to locate Praxis, even in the face of her rapidly deteriorating health due to radiation poisoning, the cure for which could only be found inside Praxis. With Magnus technically being unfit to take command due to the radiation poisoning that is slowly killing her, the role passes to Will by default, who then decides to take the risk of working with Worth to save Magnus. Magnus lodges her protests at his decision but does not challenge his authority, accepting that according to the protocols she herself had drafted, Will was in charge until she made a full recovery. Will and his team succeed in finding a cure for Magnus, but his decision to allow Worth a way back to Praxis has unintended and far reaching consequences, indirectly leading to the destruction of the city at Worth's hands.
Psych Worm Dream World
In the dream world created by exposure to a Psych Worm's venom, Will is a Cardiac Surgeon who presumably works at the Hospital, living in a house that is assumed to reside in a neighboring suburb located on the coastline just outside of Old City. Will's mother Mary Anne Zimmerman is still alive and he is married to Abby Corrigan who is currently pregnant with their supposed son, Roy Zimmerman. Will lives across the street from Helen Druitt, and has a recurring issue with her cat named Henry who likes to climb on top of his BMW.
- Dr. Helen Magnus
- Magnus saved Will's life when he was attacked by a Giant Lizard Creature as a young boy. Unable to save his mother, she secretly watched over him well into his adulthood, and eventually recruited him as her protégé and could-be replacement should anything happen to her. They greatly respect each other, and Will relies on her as a mentor as much as she relies on him as her second-in-command.
- Will was in a relationship with her for at least 2-years (both of them living together at his apartment), but they broke up just prior to his introduction to Dr. Magnus and the Sanctuary Network. Meg seemed to still have feelings for him, but found it impossible to live with him any longer. When she called to check-up on him to see how he's been (as he seeming completely vanished from regular life and communication with people), she misunderstood his demanding secretive involvement with the Old City Sanctuary to believe Will had instead already started a new romantic relationship with another woman, to which she felt hurt and wished him all the best before hanging up on him.
- Clara Griffin
- Will and Clara share a kiss not long after meeting during the crisis surrounding the Cabal's Lazarus Virus. They have a long-distance relationship for some time, with him staying in Old City and her living in the UK Sanctuary. When the facility comes under attack by the Cabal's Super Abnormals, Will asks Clara to evacuate with the other residents, but she refuses to go, and is killed in the fighting.
- Abby Corrigan
- Will and Abby first met during a course at the FBI Academy in Quantico, Virginia but she did not leave much of an impression, as he could not remember her when she came to see him at the Old City Sanctuary in early-2010. However, at that point, they were immediately attracted to each other, and ended up going on a date shortly after solving the case Abby came to discuss. This proved difficult, as they got into trouble with abnormals on both of their first dates. As of now, the two are in a happy relationship.
- Will serves as one of the main protagonists of the series, initially being as unfamiliar with the world of Sanctuary as the viewer.
- Although he is commonly called "Will", his full first name is shown to be "William" on his file in the opening credits. Several characters, like Watson and Kate, also call him "William" on occasion.
- In Episode 4x11 - "The Depths", Will displays somewhat severe claustrophobia.
- Also in Episode 4x11 - "The Depths", Will comes to the realization that it was Magnus who funded his scholarship to Harvard University. He then accuses her of directing his life to always work for her at the Sanctuary, to which she rebuffs him, stating that on her first walk through life that she had no idea if bringing him on board on the Sanctuary team would have been a brilliant move or complete disaster. That for as much as Will thinks she has power over events and peoples lives like strategically controlling pieces on a chess board, that she actually doesn't, having had been forced to let terrible things and historical events play out exactly as they had happened for the past 113-years on her trip back through time.
There are some small character differences between Will's portrayal in the Web Series and that in the TV Series; being changed from one that was seen as being of a pure medical background to one that was more aligned with law enforcement.
- In the Web Series, Will was a resident psychiatrist at the Hospital who's former patient Larry Tolson was wrongly believed to be behind in the murders committed by Alexei's appendage. As a child, Will was exposed to abnormals through being life-long traumatized by Bigfoot trespassing into his house at 1123 Seneca Boulevard, East Hills, Barron County after Will had just previously spent the night watching a 'Monster' program on TV while his parents were out and he was being watched by a Babysitter.
- In the TV Series, this was changed to Will having joined the FBI after medical school for psychiatry, eventually getting kicked out of the Bureau to then work for the OCPD as a forensic shrink (with very loose ties to the Hospital) for 6-months prior to Magnus recruiting him. As a child, Will was exposed to abnormals when his mother was killed during a night they spent at an unnamed campground, leading to a lifelong trauma over his mother's death.
- As of his 2011 Birthday in Episode 4x06 - "Homecoming".
- Kate was his girlfriend and mother of his son in Episode 2x05 - "Pavor Nocturnus".
- Abby was his wife and mother of his unborn child in Episode 3x19 - "Out of the Blue".
- His grandfather Jack was American.
- His mother Mary Anne was from Dubin.
- Episode 2x05 - "Pavor Nocturnus"