- "You're a good doctor, and the world needs good doctors, you ass!"
- —Connor to Will
William "Will" Halstead is a former plastic surgeon and a current first-year Emergency Medicine Attending at Gaffney Chicago Medical Center.
Will was born to Pat Halstead and his wife and raised in Canaryville, Chicago with his younger brother Jay Halstead. Their family have lived in Canaryville for three generations. Will's father always viewed him as a disappointment, especially when Will decided to go to college rather than going straight to work. Because of this, Will put himself through college with no support from his father. His brother went into Army and later into Chicago PD to become a detective. Will's mother died of cancer.
Jay Halstead is Will's brother and a detective for the Chicago PD. Jay often has to bail Will out of trouble. During a Chicago PD and Law and Order: SVU crossover Will was questioned against his brother wishes, blindsided. Will wanted to help the case even though Jay did not agree with it.
Will is close to Dr. Natalie Manning and admits to have a crush on her. He always looks out for her. However, she has a lot going on with her life at the moment and just isn't at a place where she can see herself with anyone after Jeff. They kissed in the episode Clarity.
He has constant arguments/disagreements with Connor Rhodes over medical procedures, but their friendship has started to grow in recent episodes, evident in Connor helping Will out during his placebo trial with the patient Jennifer Baker.
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.
Will is about to commit career suicide. However, Connor stops him from making a big mistake. He tells him Will is a good doctor and the world needs good doctors. Will found out from Zoe that Jennifer was on the placebo. He was about to tell her.
Jennifer Baker is released from the Hospital as she is too ill to continue the trial. She passes away at her home, with her family. Dr. Halstead attends the funeral. Her husband, Sal Baker, thanks him for not giving up on his wife. Will is sorry she had to go through it all for a trial that ended up giving her the placebo and not the drug. However, he has to move on knowing he did the best he could. Jay, his brother, helps him see that.
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. At the end, he rewatches her say that you should always "treat the patient and not the disease" and this should be he 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.
|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"||"..."||"..."||"..."|