Fans of Blue Bloods have been able to see some of their favorite characters return during the 2025 TV schedule, thanks to spinoff series Boston Blue. In addition to Donnie Wahlberg, who stars as Detective Danny Reagan, Bridget Moynahan reprised her role as Erin Reagan in the premiere, while Marisa Ramirez has been recurring as Maria Baez. The show also brought back Danny’s youngest son, Sean, though he's now played by Mika Amonsen, who's opening up about taking over the role.
When it was announced that Amonsen would be playing Sean in Boston Blue, it came as a surprise. Andrew Terraciano played the character during all 14 seasons of Blue Bloods, while his big brother, Tony, played Sean’s older brother, Jack. Boston showrunners Brandon Margolis and Brandon Sonnier previously explained the recasting, saying that it had to do with picking up the series with the story in progress and showing that Sean went through the Academy, which made sense. But it was a stressful time for Amonsen when he landed the role, as he recalled to Us Weekly:
