He was formerly a captain with the Chicago Fire Department and the officer in charge of Truck 81 at Firehouse 51 , but transferred when he moved to Oregon. He was portrayed by Jesse Spencer. He is the only son and second child of Nancy and Gregory Casey. He has an older sister, Christie , and a niece named Violet. When he was a teenager, his mother struggled under the abuse of her husband. When she finally snapped after Gregory started verbally abusing Matt , she shot and killed Gregory after letting herself into his home using a key that Matt had left out.
Christie wasn't living with them at that time, therefore, she was adamant on supporting her father's side on every hearing her mother had while she was in prison. This drove Matt and Christie apart. Casey and Severide are at odds at the beginning of the season, with each blaming the other for the death of fellow firefighter Andy Darden. Casey is in a relationship with Hallie Thomas and is engaged to her, but the two later break up. Casey gets back together with Hallie when she returns from a long trip and the two are happy until she is the victim of a fire at a clinic where she worked part time.
Firehouse 51 responds to the fire and he manages to get her out, but she later dies at the hospital. He cries in the arms of one of his firefighting friends. He's very disturbed by her death and tries to dig deeper and find out what happened with the help of Antonio Dawson.
It's clear that something is going on, but the head of the clinic refuses to cooperate and they meet a dead end. After Dawson breaks up with Mills , she helps Casey through the death of Hallie and the two start dating later in the season. Heather , meanwhile, ends up in a car crash that kills her best friend and she asks him to take care of her children, Griffin and Ben, while she serves an 18 month prison sentence. He agrees since he was close friends with her late husband Andy and Dawson helps him through it until Heather is released early due to overcrowding.
Heather thanks him for taking care of her boys, and even though they have grown close to him, she decides to move to Florida. During Shoved in My Face , Casey is experiencing flashbacks of the fire and suffers repeated episodes when he cannot open his locker. He and Dawson also tell the rest of the squad about their relationship. On a call, Casey saves a man named Jeremy, who had a pipe go through his neck.
