Inside Boston Blue’s Struggles with Donnie Wahlberg’s Son Sean’s Relationship Challenges

Boston Blue has just added a romantic interest for Sean, complicating his relationship with dad Danny even further.

In the episode airing Friday, November 21, Sean (Mika Amonsen) experienced an unusual meet cute with Penny (Xochitl Gomez), who surprisingly has a criminal background. Danny (Donnie Wahlberg), Sean’s father, was particularly unhappy about the idea of his son dating someone with a felony record.

Although Danny eventually warmed up to the idea by the episode’s conclusion, Penny’s presence in Sean’s life may lead to ongoing family tensions.

“As Danny puts it, ‘That crook.’ He really enjoys saying that,” Amonsen joked in an exclusive chat with Us Weekly. “But we face our challenges. I’ll let viewers stay tuned to find out where things go and whether Penny comes back.”

A CBS press release reveals that the 19-year-old Gomez will guest star as Penny in multiple episodes of the Blue Bloods spin-off.

“She’ll be around, and her relationship with Sean will continue to develop,” Amonsen hinted. “The challenges posed by Danny impact Sean as well. For him, this feels like a first serious girlfriend, and he learns about balancing work and life.”

Boston Blue, which launched in October, delves deeper into Danny’s story, following his earlier appearances on Blue Bloods, which aired from 2010 to 2024. The spin-off has also allowed for a closer look at Danny’s efforts to mend his relationship with Sean throughout the season.

“Viewers will see different forms of pushback from Danny. However, there comes a moment when Danny realizes his son is an adult. Even when he disagrees, he ultimately wants Sean to be happy,” Amonsen elaborated. “There’s a limit to what Danny can impose, especially since Sean is at an age where he makes his own choices.”

He added: “No matter what Danny thinks, he takes a moment to say, ‘I just want you to be happy.’ This theme recurs throughout several episodes as both Danny and Sean experience growth. We witness significant character development for Danny, especially in response to Sean’s changes.”

Having the reconciliation between Danny and Sean as a central theme of the show has enabled Amonsen and Wahlberg, 56, to strengthen their on-screen chemistry.

“The process has been surprisingly smooth. Donnie makes everything simple. I had a good grasp of the character established in Blue Bloods and discussed it with the showrunners and writers,” he shared. “[We talked about what they wanted to explore and how to develop the role].”

Amonsen and Wahlberg focused heavily on the dynamics between Danny and Sean. “Donnie provided a wealth of knowledge, given his extensive history with the show,” he remarked. “Whenever I had queries, it was a relaxed environment, which felt very natural with him. His fatherly presence was invaluable, and he’s been an amazing mentor in navigating this role. I couldn’t ask for a better co-star.”

The positive experience extends beyond Danny and Sean. Amonsen has found depth in Sean’s character through his work alongside Marcus Scribner‘s Jonah.

“Working with Marcus is just as enjoyable as it appears on screen. He’s fantastic. The genuine friendship you see between Jonah and Sean mirrors our real-life camaraderie. We hang out in between scenes and share plenty of laughs. It’s a great experience,” Amonsen noted. “He feels like a brother, and their bond transcends mere friendship, showcasing the essence of partnership in their job.”

He continued: “As they tackle challenging situations, their support for each other goes beyond traditional friendship. It embodies the partnership that the job demands, reflecting their unwavering commitment to one another.”

For Amonsen, the highlight of portraying Sean has been the chance to “explore” the character’s current evolution.

“My dad was a fan of the series, and we watched it multiple times. However, I hadn’t delved deeply into it until the audition. I knew it was based on Blue Bloods, but everything happened so quickly,” he recounted. “In about a week, I was thrust into this role. I binge-watched as much as I could, focusing on the later seasons to grasp Sean’s character heading into adulthood and his relationship with Danny.”

Boston Blue airs on CBS on Fridays at 10 p.m. ET.