A Fan Favorite From the Very Beginning
When Chicago Fire premiered in 2012, Charlie Barnett’s portrayal of Peter Mills made an instant impression. As a rookie firefighter following in his late father’s heroic footsteps, Mills brought heart, humility, and drive to Firehouse 51. His early struggles to earn respect on Truck 81, his climb onto Rescue Squad 3, and later, his temporary transition to Ambulance 61 after an injury, made him one of the most multi-dimensional characters in the show’s early seasons.
Add to that his complicated romance with Gabby Dawson (Monica Raymund) and his quiet resilience, and it’s no wonder Mills became a character that fans still miss. But in 2015, after more than 60 episodes, Barnett’s journey on Chicago Fire came to a sudden halt—with no warning to the audience or, it turns out, much to the actor himself.
“It Broke Me”: Barnett Opens Up About His Exit
Speaking in an emotional interview with Digital Spy, Barnett reflected on the toll his departure took:
“I was really sad to be let go. It broke me for quite a long time.”
The actor explained that, like many cast members, he didn’t anticipate how massive Chicago Fire would become. He described the experience as stepping into a “behemoth”—a franchise that would grow far beyond its initial ambitions, spawning Chicago P.D., Med, and Justice. Being part of that growth made his exit feel even more devastating.
Barnett also shared his heartfelt appreciation for the show, saying that while he never wanted to leave, he remains proud of the time he spent at Firehouse 51.
A Goodbye That Felt Too Sudden
Peter Mills was written off in Season 3, Episode 20: “You Know Where to Find Me.” The storyline saw him leave Chicago to help run a family restaurant in North Carolina, stepping away from firefighting. But for fans, it never felt like the organic end to such a central character—especially one who had been so integral to the heart of the series.
Barnett addressed this on Twitter at the time, writing:
“If I had my way, I wouldn’t be leaving… but I can’t deny the time I had was beyond amazing.”
Life After Firehouse 51
Though Peter Mills may have disappeared from the One Chicago universe, Charlie Barnett’s career has soared. He’s since taken on standout roles in acclaimed series like Orange Is the New Black, Russian Doll, and You. Yet for many fans, he will always be remembered for his early days running into burning buildings—and into the hearts of Chicago Fire viewers.
