* ActorAllusion: Frank's mention of being a Marine with service in Vietnam. During ''Series/MagnumPI's'' run, Tom Selleck often wore a cap with the legend "VMO-2", which was a Marine Forward Air Control squadron out of Da Nang.
* TheDanza: Abigail Hawk plays ''Abigail'' Baker.
* DirectedByCastMember: Donnie Wahlberg (Det. Danny Reagan) directed "Manhattan Queens".
* HeyItsThatGuy:
** [[Series/BandOfBrothers Carwood Lipton]] is now an NYPD detective.
*** [[Franchise/{{Saw}} Apparently Detective Matthews]] finally learned his lesson and is now a NYPD cop
** [[Series/ThePretender Jarod]] is a detective, too ([[GeniusBonus or is he pretending?]])
** Special Agent [[Series/CriminalMinds Elle Greenaway]] guest-stars as a Russian mob queen.
** [[Series/WhiteCollar Alex Hunter]] appears as a nightclub owner.
** Frank shares a brunch with Matt Walton, better known as the Optimum cable commercial guy.
** ADA Erin Reagan-Boyle is the HotScientist in ''Film/IRobot''.
** [[Series/NYPDBlue Det. Sgt. Martinez]] must have gotten a demotion to Patrolman.
** [[Series/TheSopranos Artie Bucco]] got a new job as an NYPD Bureau Chief.
** [[Series/{{Frasier}} Dr. Lilith Sternin]] is the Inspector General!
** Robert Clohessy, who plays Sgt/Lt. Gormley, was an NYPD sergeant in a memorable scene in ''Film/{{The Avengers|2012}}'', where [[ComicBook/CaptainAmerica Steve Rogers]] helps him battle the Chitauri, and gives him a strategy to evacuate civilians out of the affected area.
** David Ramsey, aka Diggle on ''Series/{{Arrow}}''. He began his role on ''Arrow'' during his second season on ''Blue Bloods''. He has appeared somewhat less frequently since ''Arrow'' began, due to his being a character on both shows, but still remains a very important character on ''Blue Bloods''.
** Toby Leonard Moore, who plays the released SerialRapist in "Re-Do", is probably better known to ''Series/{{Daredevil 2015}}'' fans as Wilson Fisk's lieutenant James Wesley.
* TheOtherDarrin: Nicky was played by a different actress in the original pilot.
* PlayingGertrude: Tom Selleck is only 5 years younger than Len Cariou, who plays his father.
* RealLifeRelative: Jack and Sean Reagan, Danny's two boys are played by real-life brothers Tony and Andrew Terraciano.
* RealLifeWritesThePlot: Jennifer Esposito has coeliac disease and due to the condition, could no longer keep up with the grueling filming schedule required for her character. While the show writers were willing to work around it, [[http://www.hollywoodreporter.com/live-feed/jennifer-esposito-leaves-blue-bloods-381475 CBS were not]] and told the show to write her out, a decision she was ''not happy'' with.
* TheWikiRule: [[http://bluebloodstv.wikia.com/wiki/Blue_Bloods_Wiki Blue Bloods Wiki.]]
* YouMightRememberMeFrom: Creator/TomSelleck's role as Police Commissioner Frank Reagan is his first major role in quite a while, apart from a string of TV movies based on the ''Literature/JesseStone'' book series. He mentioned in an interview on ''Series/TheTalk'' that he took the job partly because the script made him cry.
----