Main •
Taylor Kinney as Lieutenant Kelly Severide, Squad Company 3 •
David Eigenberg as Firefighter Christopher Herrmann, Truck Company 81 •
Joe Minoso as Firefighter Joe Cruz, Squad Company 3 •
Christian Stolte as Lieutenant Randall "Mouch" McHolland, Engine Company 51 •
Miranda Rae Mayo as Lieutenant Stella Kidd, Truck Company 81 •
Daniel Kyri as Firefighter Darren Ritter, Truck Company 81 •
Hanako Greensmith as Paramedic in Charge Violet Mikami, Ambulance Unit 61 •
Jocelyn Hudon as Paramedic Lizzie Novak, Ambulance Unit 61 •
Brandon Larracuente as Firefighter Sal Vasquez, Truck Company 81 •
Dermot Mulroney as Battalion Chief Dom Pascal, District 4 (Episodes 1-13)
Recurring • Randy Flagler as Firefighter Harold Capp, Squad 3 • Anthony Ferraris as Firefighter Tony Ferraris, Squad 3 • Robyn Coffin as Cindy Herrmann •
Tim Hopper as Captain Tom Van Meter • Leroy S. Williams III as Firefighter Ballard, Truck 81
Special guest stars • Jake Lockett as Firefighter Sam Carver • Jesse Lee Soffer as
Jay Halstead • Tracy Spiridakos as
Hailey Upton Crossover characters •
S. Epatha Merkerson as Sharon Goodwin, executive director of Patient and Medical Services at Gaffney Chicago Medical Center •
Steven Weber as Dr. Dean Archer, Attending Physician and Board certified in Trauma Surgery •
Darren Barnet as Dr. John Frost, Emergency Pediatrics resident and former television actor ==Episodes==