Surprise Exit The 60-year-old actor will join the NBC drama as a series regular after Eamonn exited his role as Chief Wallace Boden, Deadline reported on Thursday.

While details about Mulroney’s character have not been officially revealed, sources previously told the publication that Dom began his career with the Chicago Fire Department.

Dom, who has been described as a fun-loving individual with a leadership style that is completely different from Boden’s, returns to the Windy City after 10 years as chief of police in Miami.

Fans will remember that Boden said goodbye to Firehouse 51 in the season 12 finale, when he was promoted to Deputy Commissioner of the Chicago Fire Department.

It’s unclear what Dom’s arrival will mean for Christopher Herrmann (played by David Eigenberg), the veteran firefighter Boden has tapped to succeed him.

“You just have to be yourself,” Boden tells him. “Christopher Herrmann always cared about people, listened to people. He always led with his heart.”

In a previous interview with Deadline, David, 60, said he “didn’t know that there was a natural, organic progression” for him to step into Boden’s shoes.

“I would say he felt like he had the rug pulled out from under him because I don’t think [Herrmann] saw what the Chief was telling him,” he reflected on the scene.

David added, “In the real fire service, there are firefighters who remain firefighters throughout their entire career. So when you become a lieutenant, you’re not called a firefighter. You’re a firefighter but you’re not called that anymore.

“With Herrmann, I think he would be happy to remain a firefighter. If they decide to make him an officer, that would be great because he can lead, but I don’t know that there’s a natural, organic progression for this character to step into that position. So we’ll have to see how the writers handle it,” he concluded. Meanwhile, Eamonn is expected to reprise his role as the new Deputy Commissioner in future seasons of the hit NBC drama. Eamonn, 62, isn’t the only cast member to leave the series in season 12. In March, Rome Flynn’s character Derrick Gibson was abruptly written out of the show after six episodes. Gibson left CFD to seek help for his prescription drug addiction. “I’m sad to see Gibson leave,” Flynn, 32, said of his shocking departure. “He was a character I loved playing.” His departure comes shortly after Kara Kilmer left, with her character Sylvie Brett moving to Portland, Oregon, with her husband, fire chief Matt Casey (played by Jesse Spencer). Alberto Rosende, who joined the cast as Blake Gallo in season eight, announced his decision to leave the show in December 2023. He last appeared in the season 12 premiere episode “Barely Gone.”

In a statement later shared on Instagram, Albert said it “wasn’t easy” to say goodbye to Chicago Fire, adding that “the story I got to tell is one that I’m proud of.”

Chicago Fire also stars Taylor Kinney, Miranda Rae Mayo, Joe Miñoso, Christian Stolte, Daniel Kyri, Hanako Greensmith and Jocelyn Hudon.