In season 4, Severide finds himself in a tough position after he is demoted from his Lieutenant rank due to accusations of him being a poor leader because of the number of firefighters that have either resigned or been dismissed, despite their valid reasons for leaving.
In season 11 episode "Run Like Hell", a new opportunity from Van Meter in the OFI program came to Kelly which involved an arson investigation and some rigorous training.
Dawson gets in trouble for not strictly following procedure in order to save lives, which leads to her being written up several times and butting heads with Paramedic EMS Chief Hatcher.
and Chicago Justice, Gabby is well known for being able to hold her own in a largely male-dominated occupation and an all-male firehouse; she and Shay are the only women at 51 until Brett is assigned to Ambulance 61 in season 3.
While he is going through his grief process over losing Shay, he tries to hang out with her while deeply intoxicated, yet when sober and on the job, he treats her more coolly, a behavior that visibly throws her.
They agree to keep it a secret as long as she can teach him how to cook since he's opening Molly's 2 and she has skills that she no longer gets to use, but she ends up telling Casey due to his misunderstanding of her relationship with Cruz.
In "It Wasn't Enough", her High School friend Hope Jacquinot comes for a visit and stirs up trouble, first by seeking out Severide's attention, despite Brett's warning that it is a bad idea to get involved with him as he is recovering from the death of his girlfriend.
Brett is very apologetic with her colleagues at 51 for bringing Hope into their lives and all the mess that followed, but people don't hold her responsible nor any grudges over what happened.
She also learns that Foster was a surgical resident at Lakeshore Hospital and got kicked out of the program for cheating on her medical boards evaluation, as she was going through a rough patch in her personal life during her mother's sudden illness and death.
They officially marry in season 12 episode 6 "Port in the Storm", then Sylvie moves to Oregon permanently to live with Casey, their adopted daughter Julia and the Darden boys.
In Season 8, after the death of Otis, Boden is reluctant to bring Blake Gallo into his firehouse due to his daredevil antics but is convinced by Casey and Severide to give him a chance.
His sharp instincts on the job are in stark contrast to those when he is not at the firehouse, which include taking on several "get rich quick" schemes that have left him financially precarious.
Molly's was nearly another of his failed investments as paperwork mishaps, building code issues and competition from a large sports bar located across the street threatens closure.
[9] Because Cindy is Catholic, she does not use birth control, which leads to Herrmann's much derided decision to have a vasectomy as his 20th anniversary present to her so that she does not have to go through another pregnancy without compromising her religious beliefs.
This leads him to consider transferring to another firehouse, but he ultimately decides to stay with Truck 81 after Severide pranks him into believing that the rest of the crew have placed a bet on how long he'll last at 51.
Having grown up in the gangster-infested neighborhoods of Humboldt Park where he was regularly "lulled to sleep by gunfire",[26] many of his peers were gangsters and he is constantly trying to keep his younger brother Leon out of the local gang.
The takedown is successful but comes at a cost: Leon takes a bullet and eventually leaves Chicago for his own safety and starts a new life away from gang influence in Florida.
Despite his annoyance of Mouch and Herrmann taking over the business side and credit for his hard work, the Slamigan proves to be an effective tool in the field, and he has used it on multiple occasions.
Mouch serves as union representative for the members of the station whenever they face disciplinary action or a lawsuit and is knowledgeable in the legalities and political side of the fire department.
With the help of Herrmann, he joins the race for fire union president but loses his chance to win due to his refusal to play dirty.
[11] His older brother Danny (Andy Ahrens), a firefighter at Engine 67, pranks him by dousing him with beer, dumping him in the trunk of his car wrapped up with duct tape, and dropping him off at 51 in front of a bemused Chief Boden, Lieutenant Casey, and most of Truck 81.
When news of her transfer first reached 51 it is met with much derision as Borelli, by then a popular figure with the crew of 81, had left his candidate position to join Brett at Ambulance 61 due to manpower changes.
Since then, Stella's biggest recurring theme is her on-again, off-again relationship with Kelly Severide, but even when they aren't together in season 5, she still cares for him greatly and encourages him in his new romance with Anna, a pediatric nurse in remission.
Initially, their relationship starts off great, but both her and Severide's lingering feelings for each other begin to bubble up again, especially when Kelly goes against orders to save Stella from a fire involving exploding ammunition.
The two deal with it differently with Stella leaning on her girl friends at the firehouse, but after helping Severide capture an arsonist his father was looking for, they ultimately restarted their relationship on firmer ground.
However, after showing she was capable of making command decisions and saving Severide's life from a fire, Boden recommends her to take the Lieutenant's exam and managed to get her program restarted at the firehouse.
In "The Plunge", his continued harassment takes a toll on her job when she gets called to Lakeshore Hospital where an anonymous complaint, implied to be Dr. Shaw, has been filed against both Foster and Sylvie Brett, that could potentially cause the revocation of their paramedic licenses.
In late season 2, he asks Newhouse, one of Severide's men in Squad 3 who moonlights as a private investigator, to track down his father's side of the family as he wanted to know why his mother had forbidden him to talk about his paternal relatives or contact them all these years.
His sister Elise and mother ran a family restaurant following his father's death and Mills quickly earns the favor of his colleagues at the firehouse for his cooking skills.
As their family restaurant had been burned in the previous season, his mother and sister jumped at the chance but Mills was reluctant to leave as he just returned to duty with the rescue squad.