The Real Reason Treat Williams Left Chicago Fire

Between 2013 and 2018, the late Treat Williams appeared in 16 episodes of "Chicago Fire." It's a testament to Williams' performance that he feels so ingrained in the series. Williams portrays Benny Severide, the father of Kelly Severide (Taylor Kinney). The pair have a complicated relationship, to say the least. When Benny made his "Chicago Fire" debut in Season 1, Episode 13, he and Kelly were semi-estranged. Benny wasn't much of a father figure, and Kelly even spent a few years as a teen living away from home when he discovered his father had cheated on his mother.

Nevertheless, over the course of Benny's time on "Chicago Fire," his relationship with Kelly becomes less strained. In Season 7, Benny returns to help Kelly work through a conflict at Firehouse 51. Commissioner Carl Grissom (Gary Cole) hires "Chicago Fire" villain Jerry Gorsch (Steven Boyer) as the new Assistant Deputy Commissioner, despite him being wildly underqualified. In the midst of the crisis, Benny dies of a stroke.

According to former showrunner Derek Haas, Benny's death was written into the series as a means of exploring Kelly's relationship to tragedy. "We struck the idea of Benny coming back into [Severide's] life, or needing to go to Benny to try and help with the Grissom/Gorsch of it all," Haas told One Chicago Center in 2018. "And then what if his dad died in the middle of helping him? What would that do to Kelly? We know Kelly doesn't handle tragedy the best way; he starts wrecking things in his life. So we thought, this is interesting."

Benny Severide's death was especially shocking given that it wasn't treated as a year-end climax. That was by design. "When you lay out a season, or even half-season, we're always looking for something that is going to spark story and give us a boost, in terms of emotional storytelling that we can do," Derek Haas told One Chicago Center. "A lot of times those bigger stories are left for premieres or midseason finales season finales [sic]." Some of the most devastating "Chicago Fire" deaths functioned as season-ending cliffhangers. Benny, meanwhile, made his final appearance in Season 7, Episode 5 before dying offscreen. Haas added, "So as we were laying out the season, we were like, let's do something big and daring in the middle of the first half of episodes."

In the immediate aftermath of Benny's death, Kelly learns that his father had tirelessly advocated for him, thus undoing some of the damage he had inflicted during Kelly's childhood. "Your father stepped in, Kelly," Chief Boden (Eamonn Walker) says in Episode 6. "Every bit of goodwill, every piece of political capital, every favor he was ever owed, he put it on the line to appeal to the Commissioner to back off of 51, and it worked."

When Treat Williams died in 2023, Taylor Kinney left a heartfelt remembrance. "[He] was a father figure to everyone on set," Kinney told People at the time. "I'll always relish our conversations and his uncanny ability to light up a room. We all send love, he will be missed."