The Four Times Chicago Med, Chicago P.D. And Chicago Fire Crossed Over

For fans of medical dramas, police procedurals and heroic tales, "Chicago Med," Chicago P.D." and "Chicago Fire" are the perfect viewing trilogy. In fact, the three shows continually dominate Wednesday nights (via Hollywood Reporter), and things get even more exciting when all three shows have a multi-episode crossover event, billed as #OneChicago Day by NBC. Even the actors love it when their respective shows join forces. "It's a lot of fun," former "Chicago P.D." star Sophia Bush told TV Tango. "It's one big fraternity house. It's like your friends are coming over for a play date. We goof around a lot. And we take it seriously when we have to. But it's really just exciting." 

Unfortunately, the pandemic has put a pin in any future crossover events. "I feel bad, because we had one planned, and we had it all talked out with the showrunners of the other two shows, and we know what we're going to do, and it's enormous," "Chicago Fire" showrunner Derek Haas explained to TV Line. "But the Delta variant kind of forced our hand." In the meantime, though, these four crossover events can still be enjoyed in reruns.

Fire and Med were the first shows to have a crossover event

"Chicago Fire's" season 3 episode "I am the Apocalypse" also served as a way to introduce viewers to the doctors, nurses and staff members at Chicago Memorial, launching the successful series "Chicago Med" (per IMDb). Firehouse 51 rescues victims of an industrial chemical leak, bringing them to Chicago Memorial. But once they arrive at the hospital, a patient who claims to have a deadly airborne disease sets off a grenade. During an attempt to stop him, firefighter Kelly Severide is injured, and medical staff must race to save his life, as well as lockdown the hospital to keep the disease from getting out of the building. 

"We call them heroes ... they have a very noble profession, but I think that's a [a] very outsider perspective," "Chicago Fire" star Jesse Spencer said, per Zox. "That's where our show is good, because we're concentrating on the characters. They don't see themselves as heroes. They're guys, they're gals, and they're doing their job and it's a dangerous job and they run into these situations and they have issues with each other, and they might not necessarily like each other that much. But once they get together as a unit, they work together as a unit and that's what they do best."

Chicago P.D. joined in on the action in 2016

Chicago P.D. joined in with a storyline that kicked off during on Fire, moved on to Med, and then was completed on P.D.'s episode "Now I'm God," per SpoilerTV. That makes sense since the circumstances behind the case hit so close to home for the Intelligence Unit's Sergeant Hank Voight (played by Jason Beghe). During the event, an oncologist is accused of killing his female patients by intentionally overdosing them with chemotherapy drugs. Further complicating matters is the fact that the doctor treated Voight's wife, Camille, before she succumbed to cancer years earlier. 

While Voight is usually a tough guy, viewers got to see a more sensitive side of the character, which Beghe struggled with a bit. "I told him, 'In all these scenes, for me, when Voight's behaving or interacting with people, Camille is in the room,' and that unlocked it for him. He knows she's watching in a way. He's seeking justice for her, but he doesn't want to do it in a manner that would disappoint her," "Chicago P.D." showrunner Matt Olmstead told The Hollywood Reporter. "He's restrained because he wants to do it the right way."

This crossover had a deep impact on the Halstead brothers

A 2018 crossover event saw a raging fire in a high-rise apartment building that is later determined to be arson. One of the fire's victims is Pat Halstead, father of Dr. Will Halstead (Nick Gehlfuss) of "Chicago Med" and Detective Jay Halstead (Jesse Lee Soffer) of "Chicago P.D." While Pat initially survives the fire, smoke inhalation leads to a massive heart attack, and the brothers are eventually forced to take him off of life support. Jay then insists on working the case with the Intelligence Unit to bring in the people responsible for setting the fire (via Celeb Dirty Laundry and Pop Culture). 

During a 2021 fan event, Gehlfuss and Soffer shared that they had actually saved a woman's life for real. While driving home from dinner one night, they came upon an overturned car in a ditch. Soffer ran to call police while Gehlfuss was able to pull out the driver, who recognized her knight in shining armor. When she saw Soffer, she screamed in shock. "It was like a weird meta experience for her that like the Halstead brothers were saving her life," Soffer revealed during TV Guide's Fan Favorite panel (via Cinema Blend).

Infection was the most ambitious crossover event so far

This multi-episode story arc really left viewers on the edge of their seats. Infection focused on a deadly bacteria spreading throughout the city. As the fire department and police work together to find who is responsible for the outbreak, the medical staff at Chicago Memorial teams up with the CDC to find a cure (via TV Guide). One of the things that makes this crossover so special is that legendary producer Dick Wolf was the person who came up with storyline and worked with Derek Haas at One Chicago Day on the main plots for all three shows.

As for what inspired the them to take on this kind of story, Haas explained to Cinema Blend that it was something they "hadn't done it before. You're always looking for something to top whatever you've done in the past, and we felt like this story could make all hours feel like all three shows in a way that we hadn't done before. It seemed like a leaping off point for three exciting hours."