Andrew Terraciano says he learned he would not follow Sean Reagan to Boston Blue on the day he graduated from New York University, turning a milestone into a shock. The longtime Blue Bloods actor recalls his mother calling him in tears to say producers were considering a “different Sean” for the CBS spinoff, ending a run that stretched across 14 seasons and nearly his entire childhood on the show.
Terraciano, now 22, had played Danny Reagan’s youngest son since he was seven, growing up opposite Donnie Wahlberg as viewers watched weekly Reagan family dinners and police cases on New York streets. The decision to recast Sean for Boston Blue became public in July, when Deadline reported that Mika Amonsen would take over the role.
Showrunner Brandon Margolis later explained that the creative team wanted a slightly different version of Sean: older, working as a Boston patrol officer and carrying more of the family mantle on the job. Producers felt a new actor could signal that shift and bring what Margolis called a fresh energy to the spinoff, which follows Danny and Sean after a move from New York to Boston.
Terraciano describes those choices without bitterness. In recent interviews he has called his years as Sean “beautiful,” saying he remembers every day on set and views the role as something he could “send off into the world” for someone else to shape. He stresses that he feels joy for Amonsen and sees the character as big enough for another interpretation.
A phone call from Wahlberg softened the blow. Terraciano says his former screen father reached out soon after the graduation-day news, offering support that he describes as “beautiful” and emblematic of the family atmosphere on Blue Bloods. He still calls Wahlberg an “old friend” and says he would show up for him on any project if asked.
Fan response has been more conflicted. Longtime viewers who watched Terraciano grow up on CBS have flooded social media with messages of disappointment and appreciation, thanking him for fourteen seasons as the youngest Reagan. Some fans, though, have embraced Amonsen’s version of Sean and focused on the dynamic between father and son in the new series.
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Amonsen has addressed the backlash directly, acknowledging that replacing a familiar face can sting. He says he studied later seasons of Blue Bloods to understand Sean’s evolution and kept certain physical and character traits out of respect for what came before, while still trying to bring his own rhythm to the role.
While the casting debate plays out, Boston Blue has settled into Blue Bloods’ old Friday 10 p.m. slot, premiered on October 17 and already secured a second-season renewal after strong early ratings across broadcast and streaming. Terraciano, meanwhile, has pressed ahead with his history degree and future plans, saying he has not yet watched the spinoff but intends to give it time and “respect” when he does.
