“‘Boston Blue’ Showrunner Explains Recasting Sean Reagan’s Role”

Fans of “Blue Bloods” are discussing a notable casting change in the recently premiered spinoff, “Boston Blue.” The series launched on October 17, replacing Andrew Terraciano, who played Sean Reagan, with Mika Amonsen. Brandon Margolis, the co-showrunner of the spinoff alongside Brandon Sonnier, explained that the recasting reflects a new direction for the characters.

Key Details About the Casting Change in “Boston Blue”

• New Actor: Mika Amonsen replaces Andrew Terraciano as Sean Reagan.
• Premiere Date: “Boston Blue” debuted on October 17, 2025.
• Original Show: Terraciano, 22, portrayed Sean Reagan in “Blue Bloods” from its 2010 premiere until its conclusion in December 2024.

Insights from the Showrunners

Margolis shared that the decision to change actors was driven by the narrative’s evolution. He said, “We love Andrew and the work he did over the years on ‘Blue Bloods.’” However, the story’s shift created an opportunity for a new portrayal. The spinoff explores the relationship dynamic between Danny Reagan, now a father to a police officer, and Sean, highlighting a different energy and focus.

Margolis affirmed this sentiment: “It’s the same character, but it’s also completely different.” He praised Amonsen’s portrayal, emphasizing the blend of vulnerability and determination she brings to the role.

Brandon Wahlberg’s Perspective

Donnie Wahlberg, who reprises his role as Danny Reagan, had his reservations about returning for a spinoff. Initially uncertain, he was convinced by the potential for storytelling within this new context. “I looked at it and I saw the possibilities of weaving the ‘Blue Bloods’ world into it,” he remarked.

Wahlberg appreciated the shift in dynamics, stating that Danny’s relationship with his son—a fellow officer—adds depth to the narrative, contrasting with the original show.

Background on “Boston Blue”

Announced in February 2025, “Boston Blue” picks up after Danny Reagan joins the Boston Police Department. The storyline incorporates elements of both law enforcement and family dynamics, ensuring a fresh experience for both new and returning viewers.

With “Boston Blue” airing Fridays at 10 p.m. on CBS, fans can anticipate insightful character arcs and storytelling that reevaluates the relationships established in “Blue Bloods.”