Blue Bloods veteran cast member to join spinoff in an upcoming appearance

Boston Blue will get another appearance from a cast member from Blue Bloods. Find out who is coming and why they might be coming to Danny's doorstep.
Pictured: Donnie Wahlberg as Danny Reagan and Sonequa Martin-Green as Lena Silver. Photo: Michael Gibson/CBS ©2025 CBS Broadcasting, Inc. All Rights Reserved.
Pictured: Donnie Wahlberg as Danny Reagan and Sonequa Martin-Green as Lena Silver. Photo: Michael Gibson/CBS ©2025 CBS Broadcasting, Inc. All Rights Reserved.

Boston Blue has been gaining its footing after its predecessor, Blue Bloods, went off air. Starring Donnie Wahlberg, the spinoff has found Detective Danny Reagan now working in Boston, but his family has never been too far away. After an appearance from his sister, Erin, delighted fans of the original series, another familiar face is coming to the spinoff.

According to TVLine, Wahlberg was speaking virtually during a panel by the Television Critics Association when he revealed fans would see Danny’s grandfather, Henry, return to the screen. Len Cariou portrayed the elder Reagan for 14 seasons on Blue Bloods and is slated to make his debut on Boston Blue season 1 episode 13

Forgive Us Our Trespasses
“Forgive Us Our Trespasses” – Danny and Baez team up with Danny’s old partner, Jackie Curatola (Jennifer Esposito), to find a copycat killer emulating murders from a previous case. Also, Frank and Mayor Chase (Dylan Walsh) battle over how best to handle the city’s rising homeless population; and Jamie, Eddie and Erin team up to build evidence against a previously released man who they believe is again committing criminal assault, on the 13th season finale of BLUE BLOODS, Friday, May 19

Danny will get a visit from his grandfather amid a big decision on Boston Blue

So far, we have seen Bridget Moynihan as Danny’s sister, Erin, in the pilot episode. She is also set to return for an episode, but not the same one as their grandfather. Her appearance is set for episode 17, near the end of the season in May.

Moynihan and Cariou are not the only stars from Blue Bloods making their appearances. We will also get to see Marisa Ramirez in episode 15 as Detective Maria Baez. Baez is Danny’s former work partner, with whom he is now in a long-distance relationship.

Boston Blue has seen Danny decide to officially join the Boston Police Department, which his family will likely have opinions about. This will move him away from New York, and Maria’s appearance will likely be to establish what this means for them. Walhberg reportedly teased, “I will just tell you that it’s not resolved, and she will be back in the upcoming episodes.”

Pilot
"Pilot" - Boston Blue. Pictured (L-R): Marcus Scribner as Jonah Silver and Mika Amonsen as Sean Reagan Photo: John Medland/CBS ©2025 CBS Broadcasting, Inc. All Rights Reserved.

What led to the decision for Danny to stay in Boston?

The December midseason finale of Boston Blue saw Danny wrestling with the offer to move to Boston permanently, which is where his son, Sean, also works as a patrol officer. Things got complicated after his counterpart, Lena Silver, and her family dealt with the release of her father’s killer due to an investigation involving a corrupt ADA. This all culminated in her younger brother, a rookie officer named Jonah, being on scene when the man was killed.

Once Boston Blue returns after the hiatus, whether or not Jonah killed his father’s killer will likely be answered, as Danny will no doubt try to help the Silver family while he prepares a potential move.

While we will have to wait until April to see the return of Grandpa Reagan, fans will be able to see the aftermath of the midseason finale beginning on Friday, Feb. 27 at 10/9c. You can catch up on the entire first season of Boston Blue on Paramount+.

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