Leslie and Kelly Severide are roommates. She tries to help Severide with an injury, but it begins to break down their friendship, to the point where Shay threatens to move out. The two have a strong bond, however, and despite the hardships endured by them both they manage to stay good friends. After Clarice takes the deal from her husband and his lawyer to move to New York to be with the child she leaves Shay heartbroken once more. Shay wants a child and asks Severide if he will be the father after failing to find a suitable sperm donor. It is suspected that they do harbour a slight attraction towards one another, but not much as Shay stands for herself as a lesbian. She starts supplying her roommate Kelly Severide with painkiller drugs for his injury, potentially risking her career. She is almost discovered for this when there is a report that a bag of said drugs had gone missing.
She regularly pushes for Kelly to see a doctor about his arm, and when she discovers the true nature of his problem, prompts him to tell Chief Boden because of its severity and potential risks for both himself and his colleagues.
She is in a serious car (ambulance) accident with Gabriela Dawson when oncoming traffic rams into the rear of the stationary vehicle. Shay is seriously injured and requires hospital treatment.
Leslie is a lesbian, something Peter Mills discovered when the other firefighters tricked him into making a pass at her. She was previously in a three-year relationship with a woman named Clarice, who eventually left her only to marry and have a child with a wealthy man. This seems to have instigated the commitment issues her coworker Gabriela observed in her.
Gabriela Dawson is her fellow paramedic at the firehouse. They are often seen together and have expericenced pivotal plot moments together, such as the ambulance accident. They are very close and there is speculation that they may harbor an attraction towards one another. They comfort and help each other in many situations which is a testament to their strong friendship.
Death of Leslie Shay Edit
In reference to the episode: "Real Never Waits".
Chief Boden's wedding ceremony is interrupted when Fire House 51 is called to a building fire. Shay and Dawson follow Squad 3 into the building, they find an injured male and begin administering care. Moments after they switch places, a large explosion occurs, injuring Shay and killing her immediately.
- (To Mills): "Peter Mills, are you gay? Because I am."
- (To Dawson): "It's not too late to switch teams."
- (To Kelly about Clarice): "Turns out, I may have overestimated her lesbianism."
- (To Dawson about Mills): "Ugh. Marry him."