Meet the New Sean Reagan: Mika Amonsen Joins ‘Boston Blue’ as Donnie Wahlberg’s On-Screen Son

Danny Reagan’s youngest son Sean will look a little different when he appears alongside his dad on CBS’ upcoming drama series Boston Blue. Mika Amonsen has been cast as a series regular opposite Donnie Wahlberg on the Blue Bloods offshoot, taking over the role of Sean Reagan.

On Blue Bloods, Sean was played by Andrew Terraciano who recurred throughout the series’ 14-season run. According to sources, the recasting stems from the character taking a new creative direction on Boston Blue as he follows the Reagans’ career path into law enforcement. Meanwhile, the addition of Sean to the offshoot helps explain Danny’s move from his native New York to Boston.

On Boston Blue, Wahlberg reprises his role as NYPD Detective Danny Reagan as he takes a position with Boston PD. Once in Boston, he is paired with Detective Lena Silver (Sonequa Martin-Green), the eldest daughter of a prominent law enforcement family.

The show will find Sean in Boston where he had relocated to start a new chapter as a Boston PD patrolman. Committed himself to pursuing his family’s legacy, he wanted to do so on his own terms, which meant joining a department outside of his hometown. Danny’s (Wahlberg) decision to stay in Boston gives this father and son duo a chance to reconnect on a deeper level.

Danny’s sons Jack and Sean were played on Blue Bloods by real-life brothers Tony Terraciano and

Boston Blue' Recasts Sean Reagan, Taps Mika Amonsen As Danny's Son
Andrew Terraciano. While the oldest, Jack, left for college in Season 9 and rarely appeared on the show after that as he pursued a career in medicine, Sean remained a fixture on Blue Bloods as he went through high school and mulled various choices, including becoming a firefighter career. Last seen at the dinner table in the Blue Bloods series finale, he was off to college at the time, so Boston Blue will explain what prompted his decision to become a Boston cop.

Sean is now the first Reagan besides Danny confirmed for the new Blue Bloods universe series, with others likely to make guest appearances.

In addition to Wahlberg and Martin-Green, Amonsen joins fellow Boston Blue series regulars Maggie Lawson as Sarah Silver, Marcus Scribner as Jonah Silver, Gloria Reuben as Mae Silver and Ernie Hudson as Reverend Peters

Boston Blue, which just started production this week for a fall premiere in Blue Bloods’ Friday 10 PM time period, is produced by CBS Studios in association with Jerry Bruckheimer Television. Brandon Sonnier & Brandon Margolis showrun and executive produce. Jerry Bruckheimer, KristieAnne Reed and Wahlberg also serve as executive producers. The series will be distributed by Paramount Global Content Distribution.

Amonsen’s credits include a guest appearance on Prime Video’s Reacher and a role in Eli Roth’s horror film Thanksgiving. He will next be seen in Corin Hardy’s Whistle.

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