When Sylvie Brett and Matt Casey Became More Than Friends, Even Kara Killmer Was Taken Aback
For Chicago Fire fans, few love stories cut as deep as that of Matthew Casey (Jesse Spencer) and Gabriela Dawson (Monica Raymund). From their Season 1 slow-burn friendship to a courthouse elopement, the duo was the emotional anchor of Firehouse 51 for years. So when their relationship ended — and Dawson departed for Puerto Rico — it felt like a permanent goodbye to one of the series’ most iconic couples.
That’s why it was such a shock when Casey’s romantic arc took a sharp left turn — toward none other than Sylvie Brett (Kara Killmer), Dawson’s former partner and one-time roommate.
But if fans were surprised by the twist, they weren’t alone. Even Kara Killmer initially thought the storyline was “so wrong.”
From Supportive Friend to Something More
Introduced in Season 3 as the bubbly, big-hearted replacement for the late Leslie Shay, Sylvie Brett took time to earn her place at Firehouse 51. At first, she and Dawson didn’t click — understandable, considering Shay and Dawson had been best friends. But Brett’s earnestness and warmth eventually won Dawson over, and the two developed a close friendship on and off the ambulance.
That’s part of what made Brett’s eventual romance with Casey feel so unexpected. Brett had been one of Dawson and Casey’s biggest cheerleaders, even standing proudly beside them when they eloped. The idea of her becoming romantically involved with Casey after Dawson’s departure wasn’t just controversial to viewers — it caught Killmer herself off guard.
In past interviews, Killmer admitted that when she first heard about the Brettsey storyline, she thought, “No, that can’t happen. That’s so wrong!” Her reaction echoed what many fans were thinking. How could Brett fall for the ex-husband of her friend and mentor?
When “Wrong” Starts to Feel Right
But Chicago Fire doesn’t do shallow storytelling — and over time, the writers began to build Brett and Casey’s relationship with the same care and nuance fans expect from the series. What started as a surprising shift gradually blossomed into something more believable, more heartfelt — and yes, more complicated.
As Killmer herself later admitted, once she read the scripts and saw how the relationship unfolded naturally, she began to see the emotional logic behind it. Brett and Casey connected over shared values, mutual respect, and years of navigating personal loss together. Their romance was never about betrayal; it was about two people finding love after heartbreak.
And let’s not forget — even Dawson gave her subtle blessing from afar. By the time Brettsey officially took flight, their relationship had evolved into one of Chicago Fire’s most talked-about (and divisive) love stories.
A Franchise Built on Love and Loss
Romance has always played a starring role in the One Chicago universe. From Will and Natalie on Chicago Med to Upton and Halstead on Chicago P.D., viewers have seen relationships rise and fall under the weight of duty, danger, and heartbreak.
But Chicago Fire may be the reigning champ of emotional entanglements. With more relationships than its sister series combined, the show has delivered everything from whirlwind hookups to slow-burn love stories that span seasons. And while not every pairing has stood the test of time, the best ones — Casey & Dawson, Severide & Kidd, Cruz & Chloe — have left an indelible mark.
Where Brett and Casey Stand Now
After years of “will they, won’t they,” Brett and Casey finally found their rhythm — only to be tested by distance when Casey moved to Oregon. But in Season 12, the couple got their happy ending when they reunited and got married in a heartwarming farewell episode for Killmer.
As Killmer left Chicago Fire in 2024, she told The Hollywood Reporter she was ready for new challenges. But she also acknowledged the bittersweet nature of closing Brett’s chapter with such a defining love story.
From skepticism to genuine affection, Killmer’s journey with the Brettsey romance mirrors that of many fans — hesitant at first, but ultimately touched by the depth and sincerity of the pairing.
The Final Verdict
What once felt “so wrong” became one of Chicago Fire’s most powerful love stories — not because it replaced what came before, but because it honored every chapter along the way. For Kara Killmer, it was an arc that defied her expectations. For fans, it was proof that in the One Chicago world, love is never simple — but it’s always worth watching.
Chicago Fire returns Fall 2025 on NBC. Catch up now on Peacock.
