Cast
Jesse Spencer as Captain Matthew "Matt" Casey, Truck Company 81 (seasons 1–10; guest seasons 11–12), a lieutenant at Firehouse 51 and the officer in charge of Truck Company 81. He serves as second-in-command to Battalion Chief Wallace Boden. Casey is a skilled handyman and carpenter, freelancing as a construction contractor when off-duty. He is civic-minded and becomes an elected alderman to further serve the city. Despite his reticence and aloof demeanor, he is fiercely protective of the firefighters under him and commands their loyalty and respect. He was briefly engaged to Dr. Hallie Thomas in season 1 and, from seasons 5 to 7, was married to Gabriela Dawson. In season 6, he is promoted to captain. In the season 9 finale, he begins dating paramedic Sylvie Brett. In season 10, Casey moves to Oregon to take care of Andrew Darden's sons while maintaining a long-distance relationship with Brett. He later returns in the season finale to attend Severide and Kidd's wedding. In the season 11 premiere, Brett breaks up with him, feeling that they had grown apart due to the distance. In the season 11 finale, he returns to Chicago and proposes to Sylvie. They married in season 12.
Taylor Kinney as Captain Kelly Severide, Rescue Squad 3, a Lieutenant at Firehouse 51, and the officer in charge of Squad 3. In contrast to Casey, he is charismatic and portrayed as something of a "ladies' man". He and Casey have been friends since their days at the CFD Academy. His father was Battalion Chief Benny Severide, a longtime friend of Boden and Henry Mills, father of Candidate Peter Mills. In the season 4 finale, he begins dating Stella Kidd. In season 9, they become engaged. In season 10, they get married. In season 14, he attempts to succeed Dom Pascal as Firehouse 51's Battalion Chief. In the season 14 finale, Chief Pascal informed him that his promotion to Captain had gone through. Severide was given two options: Become deputy to Captain Van Meter at OFI, or become the commanding officer at 51.
Monica Raymund as Paramedic in Charge Gabriela "Gabby" Dawson, Ambulance 61 (seasons 1–6; guest seasons 7–8), the younger sister of Detective Antonio Dawson. Dawson is one of the few women at 51 and is usually treated as a sister by the men. She is the Paramedic in Charge of Ambulance 61, but also attends fire academy training to become a firefighter and joins Truck 81. She later transfers back to Ambulance 61 to provide cover for Jimmy Borelli and becomes a foster parent. In season 1, she briefly dates Peter Mills. From seasons 5 to 7, she was married to Casey. In the season 6 finale, she left Chicago to head a rescue-and-relief unit in Puerto Rico, but briefly returned to say goodbye to Casey in the season 7 premiere and again for a charity ball in season 8.
Lauren German as Paramedic Leslie Elizabeth Shay, Ambulance 61 (seasons 1–2; guest season 3), an experienced paramedic. Shay was the designated ambulance driver and was well-liked by the mostly male crew of 51. She and Kelly Severide shared an apartment as roommates and were best friends. She was openly lesbian and often cracked self-deprecating jokes about it. In the season 3 premiere's continuation of the season 2 finale, she was killed when a serial arsonist intentionally set a trap for first responders. She is then memorialized by her co-workers with an inscription painted on the cab door of Ambulance 61.
Charlie Barnett as Firefighter/Paramedic in Charge Peter Mills, Truck 81, Squad 3, Ambulance 61 (seasons 1–3), a candidate on Truck 81, following in his deceased father's footsteps. After proving his capabilities as a firefighter, he earns a spot on Squad 3. After losing his firefighter certification due to injury, he transfers to Ambulance 61 to keep working. He eventually recovers and earns his spot back on the squad, but chooses to leave Chicago to work with his family in North Carolina. He briefly dates Gabriela Dawson in season 1.
David Eigenberg as Firefighter (Ex-Captain and Ex-Lieutenant) Christopher Herrmann, previously Truck 81, Engine 51, one of the senior firefighters at 51, he serves on Truck 81 before he passes the lieutenant exam, after five previous attempts, and is officially promoted to Lieutenant in season 7, and takes over as officer in charge of Engine Company 51. As a Lieutenant, he serves as fourth-in-command to Battalion Chief Wallace Boden. A father figure to the firehouse, the men and women often come to him for advice. He, Otis, and Dawson jointly invest in a small bar, which they call Molly's. Molly's is also featured on Chicago P.D. and Chicago Med as a favorite hangout of cops and medical personnel. In season 13, Boden persuades Herrmann to take the Captain's exam, and despite his doubts, Herrmann passes the exam and is promoted to Captain. In the season 13 finale, Herrmann voluntarily turns in his Captain's bugles to allow for Mouch to take the Lieutenant spot on Engine and is demoted to firefighter. As part of this, he moved back to Truck 81.
Eamonn Walker as 1st Deputy Commissioner Wallace Boden, Battalion 25 (seasons 1–12; guest season 13), he oversees the firefighters and paramedics of Truck 81, Engine 51, Squad 3 and Ambulance 61 at Firehouse 51. A longtime veteran of the CFD, he is extremely protective of the men and women who serve under him, putting his career on the line several times to help them. He is married to Donna, a teacher, and they have a son named Terrance, who was born in season 3. In season 10, he was promoted to Deputy District Chief. In the season 12 finale, he was appointed as the new Deputy Commissioner of the CFD. In season 13, he returns to investigate a dangerous fire that caused a firefighter to be left trapped inside a burning building.
Yuri Sardarov as Firefighter Brian "Otis" Zvonecek, Truck 81 (recurring season 1; seasons 2–8), the latest candidate assigned to 81 before Mills' assignment. He is routinely assigned to work on elevators, and his nickname came from the Otis Elevator Company. Otis became the driver after Joe Cruz transferred to Squad 3. In the season 8 premiere's continuation of the season 7 finale, he was fatally wounded and died with Cruz by his side in the hospital.
Christian Stolte as Lieutenant Randall "Mouch" McHolland, Truck 81 (recurring season 1; season 2–present), another of 51's senior firefighters, Mouch is the de facto "legal advisor" of 51 and is their union representative. His nickname is a portmanteau of "man" and "couch" since he is almost always seen sitting on the couch in the lounge watching television when not on a call. In season 4, he marries Sergeant Trudy Platt. In season 13, he is promoted to Lieutenant, although he remained Senior Firefighter aboard Truck 81 with Lieutenant Kidd as the senior officer until the season 13 finale, when he was promoted to Lieutenant of Engine 51. He later moved to another firehouse when his engine was decommissioned, but returned after Engine 51 was recommissioned.
Joe Minoso as Firefighter Josef "Joe" Cruz, Squad 3 (recurring season 1; main season 2–14; guest season 15;), a native of the gangster-infested neighborhood of Humboldt Park, he spends the first two seasons constantly trying to bail his younger brother out of trouble. In season 3, he briefly dates Sylvie Brett. In the season 3 finale, he transfers to Squad 3. In season 8, he marries Chloe Allen. He was formerly the designated driver for Truck 81 before his transfer to Squad 3. In season 10, his son is born, and they name him Brian Leon "Otis" Cruz. In the season 14 episode, "Firehouse 66", he told Severide that Chloe was pregnant. In the season 14 finale, he and Chloe found out that they were expecting twin girls.
Teri Reeves as Dr. Hallie Thomas (season 1), Casey's ex-fiancée. They broke up due to differing views, her hectic schedule, and his irregular hours, which prevented them from spending much time together, but they remained friends. They briefly rekindled their relationship until she was murdered in a fire as part of a cover-up after she discovered one of her colleagues was selling medication to drug dealers.
Kara Killmer as Paramedic in Charge Sylvie Brett, Ambulance 61 (seasons 3–12), a paramedic who joins Ambulance 61 in season three, replacing Leslie Shay after her death. She is from Fowlerton, Indiana, and is a "runaway bride" who goes up I-65 to Chicago. Initially, she has difficulty adjusting to city life due to her naivety, as shown by how she leaves cash out on the table with the windows open and rents an apartment in a neighborhood known for crime because the rent was cheap. She briefly dates Joe Cruz in season 3 and shares an apartment with Dawson before the latter's marriage to Casey. After her third partner, Jessica Chilton, is fired for drinking on the job, Sylvie is promoted to Paramedic in Charge in season 4. She dates Dawson's brother, Antonio, on and off from seasons 5 to 6 and is also briefly engaged to Chaplain Kyle Sheffield from seasons 7 to 8. In the season 9 finale, she begins dating Casey, and in season 10, she begins a long-distance relationship with Casey when he moves to Oregon, which she later ends in the season 11 premiere after feeling they have grown apart by distance. In the season 11 finale, Casey returns to Chicago and proposes to Sylvie. They married in season 12.
Dora Madison as Paramedic in Charge Jessica "Chili" Chilton (recurring season 3; main season 4), brought in to replace Peter Mills as the new Paramedic in Charge. Her arrival is initially met with some frostiness from the rest of the crew since they were still getting over Mills' sudden departure. She was previously with a firehouse in the West Side and is experienced in dealing with victims of major trauma. She briefly dates Jimmy Borelli in season 4. She is later fired by Chief Boden after the death of her sister causes her to nearly kill a patient by giving them the wrong medicine, and relapse into alcoholism. After she is fired, she calls Severide for help, and he takes her to an Alcoholics Anonymous meeting.
Steven R. McQueen as Firefighter Candidate James "Jimmy" Borrelli (seasons 4–5), introduced in the season 4 premiere as a new candidate assigned to Truck 81. He briefly dates Jessica "Chili" Chilton in season 4 and also briefly replaces her as a paramedic on Ambulance 61 after Chilton is fired. Early in season 5, after his brother dies in a collapsed building, he blames Chief Boden and transfers back to Truck 81. Shortly thereafter, he is critically injured by an explosion that results in the loss of his left eye, thus ending his firefighting career.
Miranda Rae Mayo as Lieutenant Stella Kidd, Truck 81 (recurring season 4; main season 5–present), introduced in season 4 as Jimmy Borelli's replacement on Truck 81. She briefly replaces Otis as driver in season 6 and permanently replaces him after his death in season 8. In season 9, after passing the exams, she is promoted to Lieutenant. In the season 4 finale, she begins dating Lieutenant Kelly Severide. In season 9, they become engaged. In the season 10 finale, they get married.
Annie Ilonzeh as Paramedic Emily Foster, Ambulance 61 (seasons 7–8), a former medical student who replaces Gabriela Dawson on Ambulance 61. In the season 8 finale, she reapplies to medical school, and in the season 9 premiere, Brett says she was accepted back and is working in a COVID-19 ward.
Alberto Rosende as Firefighter Blake Gallo, Truck 81 (seasons 8–12), Firehouse 51's latest recruit on Truck 81, replacing Brian "Otis" Zvonecek after his death. Gallo became a firefighter after he lost his entire family and house in a fire. He leaves in the season 12 premiere, in which it is revealed he has opted to move to Michigan to be near his relatives.
Daniel Kyri as Firefighter Darren Ritter, Engine 51 (recurring seasons 7–8; main seasons 9–13, guest season 14), Herrmann forcibly transfers Firefighter Barnes for his disrespect and Mouch suggests Ritter as a replacement. Previously with Engine 37, Mouch helped Ritter when Ritter froze up during a fire, and Ritter ended up making his first save. He is openly gay. In season 14, he leaves after his boyfriend, Officer Dwayne Monroe, is shot while on duty in New York City.
Adriyan Rae as Paramedic Gianna Mackey, Ambulance 61 (season 9), Emily Foster's replacement on Ambulance 61. Gianna grew up in the same neighborhood as Cruz, who recommended her for the job after Foster left and is very protective of her. She quickly makes a good impression on her co-workers and enters a casual relationship with Blake Gallo. She transfers out of Firehouse 51 after being offered a spot at a new firehouse with better advancement opportunities.
Hanako Greensmith as Paramedic in Charge Violet Mikami (recurring seasons 8–9; main season 10–present), a paramedic from Firehouse 20 and Blake Gallo's old rival from the fire academy. She and Gallo briefly dated in season 8. In season 9, Chief Boden asks her to temporarily transfer to Firehouse 51 to fill the spot on Ambulance 61 after Gianna Mackey leaves, and Brett soon convinces her to transfer to Firehouse 51 permanently. Following Sylvie Brett's departure in season 12, Violet was promoted to Paramedic in Charge. In the season 14 episode "All in the Blood", Violet and Novak come up with the idea of starting a program to train firefighters as medics to take pressure off of ambulance crews.
Jake Lockett as Firefighter Samuel "Sam" Carver (recurring seasons 11–12; main season 13; guest season 14), a former rival of Kidd's from the academy recruited to Truck 81. Proving himself a solid firefighter, Carver takes time to warm up to the crew. He works through issues of his own uncaring family and eventually accepts the genuine camaraderie of Firehouse 51. An off-duty carouser and sometimes womanizer, he eases into a romance with Violet by the end of season 12. When the relationship stalls, Carver backslides into destructive behavior, resulting in his attending 12-step meetings for alcoholism and rehab. In the season 13 finale, he revealed he was transferring to the Denver Fire Department to support his sobriety and make a fresh start. In the season 14 episode "Frostbite Blue", Carver returned to 51 with his Denver company to talk with Violet about the Joint-Duty Program.
Jocelyn Hudon as Paramedic Lyla "Lizzie" Novak, (recurring season 12; main season 13–present), Brett's replacement on Ambulance 61, a free-spirited paramedic who preferred to float from firehouse to firehouse until she embraced the stability of 51. Novak is flirtatious with a mischievous sense of humor, but shows herself to be an advocate for the victims she encounters daily on the job.
Dermot Mulroney as Battalion Chief Dominic "Dom" Pascal, Battalion 25 (seasons 13–15), Boden's replacement as Battalion Chief of Firehouse 51. He is a stoic, dark-humored leader who has returned to Chicago to reunite with his estranged wife after dealing with corruption at his former post in Miami. Pascal's scrutinizing style differs from Boden's, but he quickly establishes respect and allegiance among the crew at 51. He is widowed by a car accident, and he works through his grief by staying on duty. He was let go by the CFD brass after he had been arrested by the FBI for obstructing a federal investigation, and after the charges were dropped, he left Severide as Firehouse 51's commanding officer.
Brandon Larracuente as Firefighter Salvador "Sal" Vasquez (season 14), a cocky new firefighter and driver for Truck 81. He used to be in the police academy and has a reputation for disobeying his superiors' orders if he sees fit.
Da'Vinchi as Firefighter Candidate Marcus Burke (season 15)
