Let’s be honest: The One Chicago universe isn't exactly a Hallmark movie.
Usually, December in Chicago means brutal cliffhangers, tragic deaths, or Hank Voight looking sad in the snow. Chicago PD basically refuses to acknowledge joy (it is the undisputed Grinch of the franchise), but Fire and Med have occasionally paused the trauma long enough to give us some holiday spirit.
We went back through the archives to find the episodes that actually feel like Christmas, ranked by how much they make you miss the "good old days."
1. Merry Christmas, Etc. (Chicago Fire S1E10)
The Vibe: The Golden Era
Why it wins: This isn't just a holiday episode; it is a time capsule.
Aired in 2012, this episode hits different in 2025. You have the original squad—Shay, Otis, Mills—all alive and happy. The plot balances the darkness (Cruz trying to save his brother Leon from a gang) with the light (Casey and Dawson at a fancy holiday party).
It captures the exact "found family" energy that made us fall in love with Firehouse 51 in the first place. Watching Shay and Severide banter in their prime is enough to make any long-time fan emotional. It is the undisputed king of One Chicago holidays.
2. Secret Santa Has a Gift for You (Chicago Med S7E9)
The Vibe: Chaos and Cheer
Why it ranks high: Chicago Med usually leans into the tragic, but this Season 7 episode went all-in on the festive chaos.
You get the perfect mix of medical drama (patients injured by holiday decorations) and genuine character moments. The Secret Santa storyline provided some rare levity, and seeing the staff actually gather for a Christmas party felt like a reward for sticking through the darker seasons. It proves that Gaffney can be a fun place when it wants to be, minus the ending of the episode that is. Can't always get a happy ending, you know.
3. Winterfest (Chicago Fire S10E9)
The Vibe: Microbrews and Mistletoe
Why it ranks high: This is the modern classic.
Gallo, Violet, and Ritter (the "chaotic trio") debuting their microbrewery business at Winterfest is exactly the kind of low-stakes subplot fans crave amidst the fires. It was light, it was funny, and it gave us the heartwarming visual of the Firehouse 51 family celebrating together.
4. Santa Bites (Chicago Fire S3E10)
The Vibe: Relationship Drama under the Tree
Why it ranks high: This one is messy, but in a good way.
The title alone wins points. While the fire of the week (a house fire) brings the tension, the episode is remembered for the massive shift in the Casey and Dawson relationship. It wasn't the happiest Christmas, but it was a pivotal one. It serves as a reminder that even during the holidays, 51 is a place where personal lives explode just as often as the buildings.
5. Naughty or Nice (Chicago Med S3E4)
The Vibe: The Dr. Charles Reality Check
Why it ranks high: It wouldn't be Chicago Med without a little darkness.
This episode blends Christmas miracles with the show's signature cynicism. The subplot involving Dr. Charles learning a disturbing truth about the man who shot him adds a layer of psychological thriller to the holiday proceedings. It’s not "jolly," but it is fantastic television that uses the season to highlight the loneliness and complexity of the characters.
A Note on Chicago PD: If you are looking for a Chicago PD Christmas special, the Intelligence Unit apparently doesn't believe in Santa Claus, just justice, cold weather, and brooding. And honestly? We wouldn't have it any other way.