Source: This story originated with Deadline.

Spoiler warning: This article reveals major plot details from the Chicago Fire Season 15 premiere.

Chicago Fire has officially closed the book on Dermot Mulroney’s run as Battalion Chief Dominic “Dom” Pascal, with the actor making his final appearance in the NBC drama’s Season 15 premiere.

Deadline, which confirmed at the end of July that Mulroney would leave after two seasons, reported that the premiere was his last episode. The departure reshapes Firehouse 51 just as new showrunner Victor Teran takes charge of the series.

The episode resumed the story after a high-stakes Season 14 finale put the lives of much of the 51 team in danger. Although the crew emerged mostly unscathed, the new season quickly established that the firehouse’s leadership structure will be markedly different.

Severide steps into a new role

In the premiere, Severide, played by Taylor Kinney, chose the job of Chief of Firehouse 51 over an inspector position that had also been offered to him. Teran told Deadline that Severide will now be the person leading the team, even as the firehouse begins its first season without a Chief in the house.

“We only have the one episode with him I’m sad to report. It’s just the premiere,” Teran said of Mulroney. “But he plays a very critical role.”

Teran described bringing in Mulroney as part of the difficult transition that followed the departure of Wallace Boden. Eamonn Walker portrayed Boden during the show’s first 12 seasons and later returned for a guest appearance in Season 13.

“We had a very hard task when Boden left,” Teran said. “Filling his shoes was going to be an impossible task. Dermot came in and did this incredible job, and provided a bridge to what the future is going to be.”

That future places Severide at the center of the firehouse. According to Teran, the creative team had been considering the leadership change for some time and needed to conclude Dom’s story to make room for it.

“For the first time in 15 seasons, there’s not going to be a Chief in the house,” the showrunner said. “Severide is really going to be leading things, and that’s a new thing.”

Severide has not entirely abandoned his interest in inspection work, however. The premiere showed him privately continuing to use those skills as he tries to help Joe, played by Joe Minoso, clear his name. Joe has been accused of playing a role in the fire from the Season 14 finale.

During Dom’s final moments on the series, he warns Severide to move carefully while balancing his two professional passions—or face potentially serious consequences.

Mulroney reflects on his two-season run

Dom’s tenure at 51 began on uncertain ground, but the character’s evolution ultimately won over both fans and the people around him at the firehouse. Following news of his departure, Mulroney spoke warmly about his experience during an appearance at a fan convention.

“Loved every minute of it. Became friends with this incredible crew of people,” he said.

Mulroney also praised the show’s “incredible cast” and said he had been given “incredibly challenging scenes” during his time on the series. Addressing Dom’s fate, he said that “they write the character off,” adding, “We gave it our all for two seasons.”

While the premiere represents Mulroney’s confirmed final episode, the possibility of an eventual guest appearance has not been established. Deadline noted that the show’s creators and writers have occasionally brought former cast members back, as they did with Walker in Season 13.

What else is ahead for Mulroney?

Mulroney has also been a series regular on Netflix’s The Hunting Wives, in which he plays Jed Banks. He revealed in May that production had finished on the drama’s second season. Netflix subsequently renewed the series for a third season ahead of the Season 2 premiere.

The actor has also booked roles in two films, Moon People and the action picture Streets.

What Happens Next?

For Chicago Fire, Dom’s departure clears the way for a new era at 51. Severide must now lead the firehouse while quietly pursuing the investigation that could exonerate Joe—a balancing act that Dom’s final warning suggests will carry significant risks.

ShowBiz Take

Mulroney’s exit completes a leadership transition that began when longtime chief Wallace Boden left. Showrunner Victor Teran described Pascal as a bridge to the series’ future, clearing the way for Chicago Fire to operate without a chief in the house for the first time in 15 seasons.

That shift places Severide at the center of Firehouse 51 while his private inspector work creates tension between competing responsibilities. For viewers, the change offers a significant reset to the show’s established command structure; for Mulroney, it coincides with continuing roles in The Hunting Wives and two upcoming films.