who plays danny reagan's sons on blue bloods
List of Blue Bloods characters In addition to his children, Frank is also a loving grandfather to Erin's daughter, Nicky Reagan-Boyle (Sami Gayle), and Danny's two children, Jack (Tony Terraciano) and Sean Reagan (Andrew Terraciano). In one episode, it is mentioned that Frank's wife's grandfather was one of the builders on the Brooklyn Bridge in the 1870s and '80s.[4] Frank's dad's father, Charles Reagan, was an Irish immigrant who served in World War I before becoming a police officer. Charles was the one who taught him how to fish. In "Whistle Blower" (season 2, episode 10), Frank mentions his great-uncle Teddy Reagan, a member of the NYPD Mounted Unit, who spent a cold night in a boxcar with his horse, Dolly, and woke up in Pittsburgh.