Boston Blue launched on Friday, October 17, 2025 (10/9c), and immediately ignited debate across the Blue Bloods universe for one reason: the series recast Sean Reagan . Mika Amonsen now plays Sean, taking over for Andrew Terraciano after 14 years. Co-showrunner Brandon Margolis describes the choice as part of a new phase for both father and son, with Sean now a Boston Police Department rookie and Danny Reagan adjusting to being “the father to a cop.”

Why Sean Reagan was recast

Margolis lays out the creative rationale in detail. “We wanted a slightly different version of Sean,” he explains, emphasizing that the team aimed for familiarity while making room for growth once Sean joined the force. He adds that the writers “wanted to join the story in progress,” meeting Sean af

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