Chicago Fire: 10 most memorable guest appearances at Firehouse 51

Chicago Fire is known for its drama centered around the dedicated professionals of Firehouse 51. The main cast performs week after week, but a rotating cast of guest stars raises the stakes, introduces new conflicts, and fuels the action. 

Given producer Dick Wolf's extensive Law & Order background, his One Chicago universe is full of notable characters. Guest actors from acclaimed veterans to rising stars add intrigue, unpredictability, and human connection to the firefighters' lives. Their appearances often start a crisis-of-the-week or an emotional long-term storyline.

These celebrities have delighted "Chi-Hards," the show's diehard fans, for years. These guests are crucial because they play the victims, villains, and everyday people the main characters encounter. 

The show has featured real-life Chicago figures, rock legends, and actors from other major TV shows and films in memorable guest appearances. Guest-driven storylines increase emotional and physical intensity, making Firehouse 51's work unpredictable.

10 most memorable guest appearances at Firehouse 51 on Chicago Fire

The following guest stars performed well, leaving an impression on the series as a surprise cameo, returning antagonist, or new Chicago Fire member.

1) Gary Cole as Carl Grissom

Gary Cole’s performance as Carl Grissom was one of those One Chicago villains that viewers loved to dislike. Grissom was frequently a thorn in the side of the Firehouse 51 team. His character was so in demand that his appearance was delayed until later in Season 7, but it was worth the wait. Grissom was a compelling figure, especially during the second major One Chicago crossover. He was also given a great scene with Kelly Severide, where they discussed the death of Severide’s father, providing a layer of necessary vulnerability. In his final appearance, Grissom even became a small hero, showcasing the range Cole brought to the character.

2) Carl Weathers as Mark Jefferies

Late Predator and Rocky star Carl Weathers guest-starred in Season 5, Episode 3, Scorched Earth, as Illinois State Attorney Mark Jefferies. Former NFL linebacker Weathers filled the role with political energy. The Weathers-starring spin-off, Chicago Justice, was previewed in this episode. His charisma onscreen helped the team close several cases and gave Firehouse 51 legal weight.

3) Daniel Kyri plays Darren Ritter

When Daniel Kyri was introduced as Candidate Darren Ritter in Season 7, it felt like another temporary position, as many new firefighters don’t last long at Firehouse 51. However, Kyri immediately clicked with the veteran cast, adding something special to the ensemble. He quickly made viewers care about Ritter and his personal journey. Kyri was so effective in the role that he became the perfect person to break the streak of short-lived candidates, making the show better simply by being there. Though he was a leading candidate to die in the Season 7 cliffhanger, Ritter survived and became a main cast member.

4) Rush’s Alex Lifeson and Geddy Lee

Any rock legend is a great addition to the One Chicago universe, but Rush delivered an exceptional cameo in Season 4, Episode 6 ("2112"). After Firehouse 51 successfully rescued one of the band's crew members, they were rewarded with concert tickets. Backstage, firefighters from 51 met guitarist Alex Lifeson and lead singer Geddy Lee, two-thirds of the iconic band. Lifelong fan Mouch was completely starstruck. The episode's title was inspired by Rush's fourth studio album, which made a memorable connection to the show.

5) Chicago Mayor Rahm Emanuel

The One Chicago series is famous for including real details about Chicago. Is there a better way to start the franchise than with a cameo from the most important elected official in the city? Rahm Emanuel, who used to be the mayor of Chicago, was in the pilot episode in 2012 and came back for Season 7's last episode, I'm Not Leaving You. Emanuel was Chicago's mayor from 2011 to 2019, and was also in the pilot of Chicago Med. His two appearances on Chicago Fire made the firehouse setting more realistic by adding an element of real Chicago politics and power.

6) Joe Keery plays Emmett Bird

Before Joe Keery became famous for playing Steve Harrington in Stranger Things, he had a minor role as Emmett Bird in Season 3 of Chicago Fire. Emmett was born from a sperm donation, making him Mouch's half-brother. As Emmett gave the veteran firefighter a lecture on responsibility, Christian Stolte (Mouch) and Keery had great chemistry. Keery went to DePaul University in Chicago and then put out the viral song "End of Beginning," which was a love letter to the city. 

7) Teddy Sears as Chaplain Kyle Sheffield

Teddy Sears was a new addition to Chicago Fire in Season 7, playing Chaplain Kyle Sheffield. He had this uncomplicated role, as he had previously been cast as serious characters, like a difficult CTU agent in 24: Legacy. Kyle served two purposes: one by helping to flesh out Emily Foster’s backstory and becoming a sweet and charming love interest for Sylvie Brett.

8) Brett Dalton as Jason Pelham

Brett Dalton became a recurring guest star on Chicago Fire, playing Interim Lt. Jason Pelham in nine episodes from Season 10 through Season 11. A lot of people who are really into Chi know who Dalton is because he played Grant Ward on Agents of S.H.I.E.L.D. After Lt. Matthew Casey left, he became a member of Firehouse 51. Even though his start was sad and happy, he made friends right away. He moved to a different firehouse later on so that Stella Kidd could take over as lieutenant at 51. He left so that she could have the job.

9) Carl Michael Edwards Jr.

In an unexpected cameo, Carl Edwards, a retired NASCAR stock car racer, was a deliveryman in season 4, Episode 6 ("2112"). Edwards had been acting since 2005 and racing from 2004 to 2016. His short appearance was a fun surprise for NASCAR fans and an unexpected moment in the ongoing drama of Chicago Fire.

10) Annie Ilonzeh as Emily Foster

In Season 7, Annie Ilonzeh joined the cast as Emily Foster, a paramedic who took over for Gabby Dawson. She was one of the most important new guests and soon became a main cast member. Foster had an interesting backstory as a former medical student who was expelled from medical school. She worked well with Sylvie Brett, and her presence in the ambulance made the paramedic calls less predictable and more dramatic.

Chicago Fire episodes are available to stream on NBC.