Will was born to Pat Halstead and his wife and raised in Canaryville, Chicago, along with his younger brother Jay. Will's father always viewed him as a disappointment, especially when Will decided to go to college and majored in biology in undergrad rather than going straight to work. Because of this, Will put himself through college with no support from his father. His brother, Jay, became a U.S. Army Ranger (likely right out of high school) stationed in Afghanistan; after he returned from the war, he joined Chicago Police Department and became a detective. Their mother developed an unknown kind of cancer, first starting to get very ill while Jay was deployed. Will was not "around" when she died, something that Jay harbored a significant amount of resentment towards him for and Will feels very guilty about.
Prior to moving to New York, Will worked as a doctor in Sudan, although it is unclear what exactly his job entailed. After this, he worked as a plastic surgeon in New York City for several years, but was fired for an unknown reason. He came to stay with his brother initially as a temporary measure while he found a place to live and a source of income. His first day at Chicago Med took place in the Chicago Fire episode "I Am The Apocalypse", which also served as Chicago Med's backdoor pilot. He went into work late and told Jay that morning that he intended to quit after his first shift, but quickly changed his mind, deciding to keep his job and move to Chicago permanently.
Will first appears at the ribbon-cutting ceremony for Chicago Med's emergency department (presumably rebuilt because of the explosion in "I Am The Apocalypse"). Along with his coworkers, he is on-call when the train derailment occurs and treats its victims. He is the first of the group to meet Dr. Connor Rhodes, who is performing CPR on an incoming trauma patient assigned to Will. They have a short argument about the patient's treatment before Connor informs Will that as an attending, he outranks him, putting an end to the discussion. Will immediately dislikes Connor, commenting to Natalie that he's "arrogant". Natalie simply raises her eyebrows and doesn't respond, leaving Will indignantly claiming that he's not arrogant, to which Natalie (somewhat) jokingly responds "No, you just happen to know more than anybody else".
While treating Gina, a woman who has suffered a traumatic head injury in the train derailment, Will and Dr. Ethan Choi discover that she is pregnant and soon learn that she is the surrogate mother of another couple's child. The couple, Mr. and Mrs. Donahue, are deeply concerned about Gina; however, when Will and Ethan inform them that Gina needs an operation to reduce the swelling in her brain, the couple hesitates due to the possible risk to the baby.
During iNo Will has an argument with Manning when he says that her pregnancy is getting in the way of her decision making as she was choosing to use the last nitrous oxide tank they had to save the life of a newborn baby unlikely to survive rather than another patient who Will thought needed it more. He snatches the tank off her and uses it himself, saving his own patient. This angers Manning and she doesn't talk to him for a few days despite his constant apologies. She eventually forgives him.
Will told Jay that he thought Rhodes delayed in treating Herrmann when he first arrived at hospital. Jay then passed this information down to Severide who called Rhodes out on his 'mistake' in front of everyone. Rhodes was upset by this and finds out that it was Will who told them when he sees him and Jay talking later. Will apologizes and goes to see Jay, the two then argue. Will tells him he told him about Rhodes in confidentiality but Jay says he didn't tell him not to tell anyone. He tells him he won't ever tell him anything again and Jay replies that he won't get him information from the crime scenes anymore and leaves.
Manning is about to deliver her baby and her mother-in-law comes to see her. Will clearly has feelings for her but her mother-in-law catches onto this quicker than she can and is upset. She tells him to stay from her as it has only been 6 months since her husband died. He obeys immediately and doesn't see her for the next few days. This happened as Natalie gave birth to Owen. However, on that same episode, Helen realizes that there might be a chance for Natalie to go back to Seattle (where she is originally from), thus she starts to behave nicely towards Will. She figures out if Natalie starts a new romance in Chicago, she won't consider relocating back home.
Dr. Halstead puts his career on the line for a woman who reminds him of his mother. It's in this episode that it is revealed his mother died of cancer. Had she had access to the experimental drugs available she could still be alive, according to him. So, when opportunity comes to provide that chance to a cancer patient Will takes it. However, in order to do so he ,disrespects the patient's wishes and resuscitates her. Not obeying a DNR is illegal. Jennifer Baker and her family decide to file a lawsuit against the Hospital and Will.
Natalie tells Will she is tired of being his punching bag. She asks him why is it always her. Will asks her if she really doesn't know and kisses her.
Using Connor's access codes, Will reads Jennifer Baker's medical records and learns she is on the placebo. He begs Zoe to use her influence to get Jennifer on the active drug, but she refuses, and Will leaves, intending to tell Jennifer. Knowing that Will telling Jennifer Baker means the loss of his medical license, Zoe finds Connor and tells him what Will is about to do, Connor follows Will into the elevator and presses the emergency stop button, telling him that he's going to "stop another guy from ruining his life". The two have an argument that escalates into a physical fight; when Will manages to release the emergency stop, Connor pins him against the wall and says, "You're a good doctor. The world needs good doctors, you ass." The elevator doors open, but Will stays where he is.
Jennifer Baker, having become too sick to continue the trial, goes home with her family and peacefully passes away. Will attends the funeral, where Jennifer's husband, Sal Baker, thanks him for not giving up on his wife and drops the lawsuit against him. Will is seen talking to Jay about this at the end of the episode, mentioning that he feels guilty for violating her DNR and putting her through the trial when she didn't even receive the active drug. Jay tells Will that he did the best he could, and he has to move on.
As Will's last year of residency comes to an end, he gets an offer to become an attending at Chicago Med. He is ecstatic, as he wanted to continue working there but did not think the hospital board would vote in his favor. He also seems to be happy that he can continue working with Natalie, and is shown to be upset when he sees Natalie leaving the hospital with Jeff.
Will's first mentor is brought in with kidney failure and pneumonia. Everyone, including Sharon, is sure she won't make it, but Will is determined to keep going and trying. He's very emotional and wants to save Dr. Rowan and even lashes out the care home taker who comes to check in. Will replays the graduation speech Rowan gave over and over. In the end, he rewatches her say that you should always "treat the patient and not the disease" and this should be the one thing they take away from her. He decides to let her die in peace. Natalie comforts Will when he breaks down in the locker room, and Nina is upset to see them hugging each other.
Will and Natalie treat a Peds vs Auto victim.
Will makes frequent appearances in Chicago Med's sister shows Chicago P.D. and Chicago Fire, both as a doctor and as Detective Jay Halstead's younger brother.
Will is first introduced as Jay Halstead's younger brother in "Say Her Real Name", Chicago P.D. Episode 17, Season 2 when Will gets fired from his job in New York and comes to stay with Jay indefinitely. Will is initially shown as a reckless person who frequently gets into physical fights (he is involved in a bar fight in the middle of the day the very first scene he appears in and, later on in his first episode, displays several bruises on his face and tells Jay he got into "trouble"); however, this aspect of his character calms down significantly, although he is still extremely impulsive and rash.
In "Get Back To Even", the son of a close friend of Jay's sergeant Hank Voight is shot, and Voight asks Jay to contact Will, as they cannot take the child to the hospital. Will performs emergency surgery on the boy on a dining table in his house (with Jay acting as his assistant), and he survives due to Will's excellent surgical skills.
In the Chicago P.D. and Law and Order: SVU crossover episode " Number of Rats The Number of Rats", Olivia Benson initially considered Will to be a suspect in a serial murder case due to the fact that the suspect had been described as wearing scrubs and Will worked in New York at the time the killer was active there. Will was brought in ostensibly to "help", but was soon blindsided by questioning without his or his brother's knowledge. Jay was furious and demanded that the questioning end immediately; although Will wanted to help with the investigation and was willing to answer questions, Jay forced him to leave. Although Will was almost instantly cleared as a suspect, Jay was still extremely angry it happened at all and never once doubted his innocence.
Will's first day at Chicago Med took place in the Chicago Fire episode "I Am The Apocalypse", Chicago Med's backdoor pilot. He went into work at least 10 minutes late and told Jay that he intended to quit after his first shift, which Jay objected strongly to. Soon after his arrival at the hospital, a terrorist set off a grenade, blowing up the emergency room and leaving several people killed or seriously injured. As Will was not wounded in the explosion, he helped to treat people who were hurt and took charge of communicating with Firehouse 51 and Chicago P.D. At the end of the episode, he revealed to Jay that the events of the day had changed his mind and he was going to move to Chicago permanently.
Jay Halstead is Will's older brother and a detective for the Chicago P.D.
Although Jay and Will are on good terms and very close, Jay expressed some lingering resentment towards Will when he initially returns for not being there when their mother died, during which time Jay was deployed and Will was (in Jay's words) "out partying". While neither of them are close to their father, Jay, unlike Will, had not spoken to him in over two years prior to his hospitalization, and was very reluctant to see him even then. Jay seems to strongly dislike his father and exhibits a significant change in mood and demeanor whenever he is so much as mentioned; the reason for this is yet to be revealed.
Jay is extremely protective of Will and is very quick to jump to his defense. In the Chicago P.D. and Law and Order: SVU crossover episode " Number of Rats The Number of Rats", Olivia Benson initially considered Will to be a suspect in a serial murder case due to the fact that the suspect had been described as wearing scrubs and Will worked in New York at the time the killer was active there. Will was brought in ostensibly to "help", but was soon blindsided by questioning without his or his brother's knowledge. Jay was furious and demanded that the questioning end immediately; although Will wanted to help with the investigation and was willing to answer questions, Jay forced him to leave. Although Will was almost instantly cleared as a suspect, Jay was still extremely angry it happened at all and never once doubted his innocence. In the Chicago Fire episode "I Am The Apocalypse", Chicago Med's backdoor pilot, Will is inside the Emergency Department when a terrorist sets off a bomb. He is not seriously injured, but Jay is shown to be very worried about him, immediately saying "tell me you're not in there" when Will calls him from inside the building.
In When To Let Go, after being caught in an apartment fire and admitted to Chicago Med, Will and Jay's father Pat died. Will called the code, and was told by the hospital Board to keep him on the ventilator for as long as he needed. Will later found out that it was because the hospital wanted to avoid liability for the death because of a surgery Pat had a month earlier and wanted to pass the 30-day mark. Furious, he wanted to take off Pat off the ventilator and got into an argument with Jay, who refused to do it. Will apologised later on and said if Jay wanted to, they would keep their father on the ventilator for as long as he needed, after which they jointly decided to switch it off.
In Heavy is the Head, at Pat's wake, Will ran into old neighbourhood friends Tommy and Tim Burke. After checking up on his father, he found Jay waiting for him in the hospital carpark and played the recording of Will in Ray Burke's home. Will asked if Jay had been recording him, and Jay told him they had been recording Ray for money laundering, fraud and other activities. Soon, Will got caught up in the investigation and was asked to tap Ray's home. Tim and Tommy found out, and came to the hospital and took Will with them, saying Ray was sick again. They ended up in a warehouse, and trapped Jay there, threatening to kill him for what he did. However, Ray passed out and with a bleed in his brain and they held him at gunpoint to fix it. Tommy then pointed a gun at him and said he'd have to kill him, but was shot by police before he could. Jay then took him into witness-protection with Agent Lee.
RomanceNatalie Manning is one of Will's close friends and a coworker at Chicago Med. Will has had a crush on since they first met, but while it is implied that Natalie also has romantic feelings towards him, their relationship has so far never escalated beyond friendship due to the death of Natalie's husband, the birth of her son, and her failed relationship with Jeff. They kissed once in the episode Clarity, but remained friends and continued like it hadn't happened.
Will is noticeably jealous whenever Natalie is interested in someone, or vice versa. This is shown very clearly with Jeff, who he immediately dislikes due to (among other reasons) his close relationship with Natalie; at the end of Season 2, Natalie asks Jay to go to Noah's graduation party with her. Jay checks with Will, who says he's fine with it, but Jay turns her down anyway, telling Will that he "really need[s] to get it together" and ask her out.
The last scene of Season 2 suggests that Will and Natalie may have begun a romantic relationship, but there is no confirmation from either the episode or information about Season 3.
In the season 3 premiere, it was revealed that Natalie went on a 3 month sabbatical to think. Later on, Will told her that his feelings for her hadn't gone away and she revealed that she took the time off the think about him and then she kissed him.
At the end of Trust Your Gut, Will and Natalie fell asleep on the couch of the staff room, after a long shift. Before Natalie drifted off she said Will's body made a nice pillow.
At the end of Crisis Of Confidence, Will asks Jay for their mother's engagement ring, he plans on proposing to Natalie. But by the end of The Tipping Point, she learns that the women he kissed was a doctor she knew and Will runs after her and proposes anyway. Her answer is unknown.
At the start of Be My Better Half, Will and Natalie are engaged. It took a week for her to answer. However, they are already fighting other wedding plans because Natalie has already been married and wants it to be small. But in the end they agree to do the planning together.
After returning from witness-protection, Will started keeping a gun with him in All the Lonely People , and Natalie asked him to either get rid of it or leave the house. He chose the latter. But being worried about each other, she told him to come again if he left the gun, which he promised to do and even took to CPD, but in the end decided against it and left it in the car without telling Natalie. In Ghosts in the Attic, the gun was stolen from his car and Natalie ended up finding out. Upset with the secrets, she gave him the engagement ring back and broke up with him.
Natalie then started seeing the father of a baby she was treating, Philip. Philip disliked Will and the two often exchanged words when Philip came to the hospital. Philip was planning on proposing to Natalie. At the same time, Will found out that Ingrid Lee, the FBI agent who had worked on the Ray Burke case, had moved in to his neighborhood. She liked him, but then figured out that Will still in love with Natalie. She told Natalie, who went to see Will that night in With a Brave Heart, where their car was hit by Tim Burke.
After being taken into surgery, Natalie lost her memory of that night, but Will was sure that she had been coming over to get back together with him. However, Philip comes to see her and tells Natalie that he proposed, showing her a ring on her finger. Doctor Marcel says the ring wasn't there when they operated.
While she recovers, Will is critical of the way that she is treating her patients as she often gets into arguments with them. Natalie blames Will for punishing her for something she does not even remember, and Will tells Marcel that she was probably coming over to tell him it was over and that he needs to move. Doctor Marcel tells Will the same thing he told Philip - that the ring was not there when she came in that night.
Will is sure that Natalie will understand him once he tells her this. He goes to find her but she is already breaking up with Philip outside the hospital, telling him she doesn't feel right about the engagement. Will accuses Philip of using Natalie's memory loss to make her think he engaged. Natalie seems tired of them both, and tells them both to get out of her life.
Will starts dating again in I Can't Imagine the Future, where Elsa Curry also tries to ask him out. Natalie then regains her memories when she sees Philip's daughter back in the ER, remembering a similar setting to the night of the accident. She remembers and goes to find Will on the roof to tell him they should get back together and that she was wrong. Will apologises and tells her he's moved on, to her sadness. It appears they've at least gotten on civil terms.
Will’s nurse who shadows him in Season 5.
During Who Knows What Tomorrow Brings, they attend a crawfish ball, Will allows Elsa to call him by his name while they’re off duty. She takes an interest in him, while showing him how to eat crawfish. In Too Close to the Sun, Will is oblivious to Elsa implying a date to a concert thinking she only wanted to go early. When they help a patient, Elsa is critical of Will's methods but ultimately sees that he was correct and they save the patient. She apologizes for doubting him, as he accepts it and her interest grows after he says he has a natural affinity for this kind of thing. She later tries to ask him out on a date to a concert but is disappointed to see that Will already has a date.
It is unknown if she still has any romantic affections towards him.
Will meet Hannah at an offset med center and treated her addiction to drugs. He was later shocked to discover Hannah is a doctor and was skeptical of her methods. She later invite it Will to her apartment after he promised to help her.
The next day, Hannah was late for surgery and Will was angry with her and ranted at her about this even calling their encounter a mistake, to her anger. Will went as far is nearly exposing her habits to the superiors.
However, Will regrets his choice and the pair reconcile with him staying over more. When meeting someone from her past, he is upset but learns he needs to stop being critical and let her find her. At the end, he surprises Hannah with his belief in her road to recovery and they share a hug.
Will's relationship with Connor Rhodes was initially extremely antagonistic, beginning immediately after they meet due to him overriding Will's authority in the ED. Will frequently disagrees with Connor's medical opinions (possibly out of spite) and openly resents Connor's wealthy upbringing, frequently making snide comments about the differences in their childhoods.
When he discovers in "Fallback" that Connor's family owns a chain of expensive department stores, he jokes that he once went into one of the stores and the only thing he could afford was a pair of socks. Connor responds by telling Will that if his solution to their case is effective, he'll buy him a tie. Will seems to interpret this as a joke, but when his approach actually does cure their patient, he discovers a tie left for him by Connor. After this, their relationship slowly begins to improve, although they continue to fight over nearly everything.
In "Guilty", Will asks Connor to use his codes to access Jennifer Baker's medical records as a favor, as Will is not allowed to have any involvement in her case whatsoever. Connor agrees, but when he learns from Zoe that Will is planning to tell Jennifer Baker she's on the placebo, he rushes to stop him, saying that he "didn't think it [giving Will the access codes] would lead to this". He engages the emergency stop on the elevator and ends up involved in a physical struggle with Will; when Will manages to release the brakes, Connor pins him against a wall. He tells Will that "you're a good doctor. The world needs good doctors, you ass." Will eventually stops fighting and does not tell Jennifer about the drugs, retaining his job and license. They gradually start to become friends, and their conflicts with each other have significantly died down by the end of Season 2.
|Season 1 Appearances|
|Season 2 Appearances|
| "Soul Care"
| "Win Loss"
| "Natural History"
| "Brother's Keeper"
| "Extreme Measures"
| "Alternative Medicine"
| "Inherent Bias"
| "Free Will"
| "Uncharted Territory"
| "Heart Matters"
| "Graveyard Shift"
| "Mirror Mirror"
| "Theseus' Ship"
| "Cold Front"
| "Lose Yourself"
| "Prisoner's Dilemma"
| "Monday Mourning"
| "Lesson Learned"
| "Ctrl Alt"
| "Generation Gap"
| "Deliver Us"
| "White Butterflies"
| "Love Hurts"
- "Say Her Real Name"
- "Get Back To Even"
- "The Number Of Rats"
- "Life Is Fluid"
- "Natural Born Storyteller"
- "Actual Physical Violence"
- "Climbing Into Bed"
- "You Never Know Who's Who"
- "A War Zone"
- "A Shot Heard Round The World"
- "Emotional Proximity"
- "Remember The Devil"
- "Fork In The Road"
- "I Am The Apocalypse"
- "Let It Burn"
- "I Walk Away"
- "Your Day Is Coming"
- "Regarding This Wedding"
- "The Beating Heart"
- "What Happened To Courtney"
- "I Will Be Walking"
- "The Last One For Mom"
- "Kind Of A Crazy Idea"
- "A Real Wake-Up Call"
- He has had a crush on Dr. Manning since he first began working at Med.
- Will was raised Catholic, serving both as an altar boy and attending Catholic school.
- His family has lived in Canaryville for three generations.
- It is confirmed that Will is younger than Jay in the Chicago P.D. episode "Say Her Real Name" when he explicitly refers to Jay as "my older brother".
- Will has a cross tattoo on the third finger of his left hand.
- ""I'm like a little kid with a crush on a girl, so what does he pull her pigtails""
- —To Natalie
- "I became a doctor to save peoples lives!"
- —Will Halstead
- "Hey, I am not arrogant"
- —To Natalie
- ↑ "Say Her Real Name", Chicago P.D. Episode 17, Season 2.
- ↑ "Get Back To Even", Chicago P.D. Episode 18, Season 2.