The "Battle of the Badges" boxing match pits fire chief Boden against police captain "Olmstead". Writer and producer Matt Olmstead is credited as the creator of the spin-off series Chicago P.D. (2014).
For the first three seasons, patients rescued by the paramedics on board Ambo 61 were typically taken to (the fictional) Lakeshore Hospital. In 2015, the Dick Wolf-produced medical series "Chicago Med" premiered. It features the drama happening in the Emergency Department of another fictional hospital; Gaffney Chicago Medical Center. Shortly after the debut of Chicago Med, the paramedics began transporting patients almost exclusively to Gaffney, known as Chicago Med on the show. The change was never explained on Chicago Fire. However, it was acknowledged in an exchange between Paramedics Brett and Dawson after several seasons, when Brett said to Dawson, "Hey, you ever "notice we don't go to Lakeshore anymore?" Later episodes did, in fact, have the paramedics transporting patients to Lakeshore again, but relatively infrequently.