Why Did “Boston Blue” Recast Donnie Wahlberg’s On-Screen Son? All About the Decision to Replace “Blue Bloods”’ Andrew Terraciano

‘Boston Blue’ Recasts Donnie Wahlberg’s ‘Blue Bloods’ Son

A major shake-up in casting has left fans of the hit series “Boston Blue” divided. In a surprising move, it was announced in July 2025 that Andrew Terraciano would no longer be portraying Sean Reagan, the son of Danny Reagan (played by Donnie Wahlberg), in the CBS spinoff of ‘Blue Bloods’. This decision came as a shock to many fans, as Terraciano had portrayed Sean for 14 seasons alongside Wahlberg. The new series, ‘Boston Blue’, which premiered in October 2025, now features Mika Amonsen in the role of Sean, marking a significant change in the dynamic between father and son.

Co-showrunner Brandon Margolis shed light on the reasoning behind the recasting, emphasizing the need for a different energy to reflect the evolving relationship between the characters. Margolis expressed appreciation for Terraciano’s work in the original series but highlighted the importance of finding an actor who could embody the new chapter in Sean’s life. The decision to recast was solely driven by creative considerations, according to Margolis, indicating a desire to explore fresh storytelling avenues within the show.

The spinoff ‘Boston Blue’ introduces a revamped setting for the Reagan family, with Sean now serving as a patrolman in the Boston Police Department. This transition brings Danny and Sean together in the same department, providing a unique opportunity to explore the complexities of their relationship in a new light. Margolis explained that this shift opens up uncharted territory for the characters, presenting viewers with a different side to the familiar father-son duo. Despite the continuity of the characters, the recasting aims to infuse a new energy into their interactions on screen.

Fan reactions to the recasting have been mixed, with some expressing disappointment at the change while others have welcomed the fresh perspective brought by Amonsen. Comments on social media platforms highlighted the strong bond between Danny and Sean as a highlight of the series, with viewers eager to see how the new dynamics will unfold in ‘Boston Blue’. Amonsen, acknowledging the negativity surrounding the recasting, has chosen to focus on the positive responses from fans who have embraced his portrayal of Sean and the evolution of the character.

In contrast, Terraciano has not publicly commented on the recasting, but his reflections following the conclusion of ‘Blue Bloods’ indicate a sense of gratitude for the experiences gained during his time on the show. Terraciano expressed appreciation for the support and guidance received from the cast and crew, emphasising the profound impact the series had on his personal and professional growth. As the character of Sean Reagan embarks on a new journey in ‘Boston Blue’, fans eagerly anticipate the unfolding of fresh storylines and character developments in the spinoff series.

In conclusion, the decision to recast Sean Reagan in ‘Boston Blue’ represents a strategic move by the show’s creators to inject new life into the narrative and explore uncharted territories within the Reagan family dynamics. While the transition has sparked mixed reactions among fans, the introduction of Mika Amonsen as Sean signals a new chapter in the evolution of the beloved character. As the spinoff continues to unfold, audiences can expect to witness the father-son duo navigate uncharted waters and forge new connections in the vibrant backdrop of Boston’s law enforcement landscape.