The latest crossover event featuring Chicago Fire, Chicago Med, and Chicago P.D. drew strong audiences on NBC, with Chicago Med reaching 6.4 million viewers. The episodes, which aired on March 4, marked the franchise's best numbers in over a year, excluding streaming on Peacock. Production faced significant challenges due to cold weather and tight scheduling.
The One Chicago crossover aired as a three-hour event starting with Chicago Fire on March 4, followed by Chicago Med and Chicago P.D. Viewership figures showed Chicago Fire with 6.3 million total viewers, Chicago Med with a season high of 6.4 million, and Chicago P.D. with 6.1 million. These numbers represent the highest for the franchise in more than a year and do not include viewers on Peacock.
The storyline centered on a mysterious chemical attack that destroyed an airplane carrying passengers, placing first responders in peril. The event included returns by actors Jesse Lee Soffer as Jay Halstead, who left in 2022, and Tracy Spiridakos as Hailey Upton, who departed in 2024.
Produced by Wolf Entertainment and Universal Television, the crossover involved elaborate logistics. The team chartered a Boeing 737-800 aircraft and filled it with 110 passengers. An FX makeup team applied around 400 prosthetics daily and created 3,000 gel capsules using sodium bicarbonate, citric acid, and red powdered Kool-Aid.
Rebecca McGill, executive vice president of Wolf Entertainment and co-executive producer for the series, described the production as the toughest yet. "Logistically, I think this was the toughest [we’ve ever done] because, in big part, due to when we shot it. This is one of the first times we’ve actually had to shut down production because it was too cold to shoot. It was insane," McGill told Variety. Shooting at the airport was halted two days early due to extreme cold, dubbed "Chi-beria," which was colder than Antarctica.
Coordinating the cast proved challenging, as actors were filming separate episodes across Chicago but needed to appear together for the crossover. Production extended into weekends, including Super Bowl Sunday for key hospital waiting room scenes. "That was when we could get the actors for all of those big hospital scenes in the waiting room. They made a really nice day of it," McGill said.
After reviewing footage on February 26, the team found the episodes short on runtime. Additional scenes were shot on February 27, with air traffic control sequences filmed on February 28—five days before the March 4 airdate. "Everybody wants to get it right—everybody wants to make it great," McGill noted. "So we do what we have to do."
