See Also: Notable Characters Season 1 | Notable Characters Season 2 | Notable Characters Season 3 | Notable Characters Season 4 | Notable Characters Season 5 | Notable Characters Season 6 | Notable Characters Season 7 | Notable Characters Season 8
- Mike Royce - Formerly Beckett's training officer, now a bounty hunter, he comes to visit the precinct to sneak a peek at evidence in a current case that might be tied to an old case of his that leads to buried treasure.
- Natalie Rhodes is the actress selected to play Nikki Heat. Changes her appearance to mimic Beckett and tries to spend a night in researching Rook (Castle)
- Duke Jones, PI that does "background" checks on potential clients, set up "honey trapping" operation and his alibi is that he was "banging" the neighbor lady
- Charles "Chuck" Russel - street magician who disapeared in front of Beckett when she wanted to question him ... "Alakazam, jackass"
- Tobias Strange: Hottest magician in town (in more ways than one!)
- John Ragland in 1999 was the officer working Johanna Beckett's murder case. In 1992 he started down a path that eventually led to his covering up the real reason for her murder. He was murdered in front of Kate Beckett and Rick Castle in a diner.
- Gary McCallister is a retired cop, friend of John Ragland, "involved" in the cover up (and maybe more) of the murder of Johanna Beckett.
- Vulcan Simmons controls half of the drug trade in New York, never convicted. He provoked Beckett and she almost threw him through the one way mirror in the interrogation room.
- Reginald Easley Mr. Hixton's servant ...er correction by Mr. Easley, he is a Traditional English Butler ... apprenticed at Buckingham Palace. The Butler did NOT do it.
- Greg and Ty Page: the rapping ("Move that ass, Get on the floor") bank robbers from Florida, grew up with Jay Hixton and came to New York to help him with a drug pusher - to keep the pusher away from Jay's daughter.
- "Todd Shipley" The Blue Face Man, maintenance worker at an apartment building, found a money bag and he picked it up at the wrong time and the dye pack went off covering his hands and face.
- Blanca "the mail lady" calls Castle "that crazy man" (in Spanish) and Esposito agrees with her. She alibied out Damian Westlake for his wife's murder.
- Morris Hasberg is a Russian carpenter; Beckett imitates his speech patterns / accent during interrogation.
- Omar Lincoln is a "tagger"; while in interrogation he says that he would have killed the woman just to shut her up.
- Mark Fallon of the Department of Homeland Security. He takes over the case of the dirty bomb and continued the role in
Countdown. Known around the precinct as "Captain Douche Bag, DHS" (but no one called him that). He has to be hard nosed because of his job.
- Fariq Yusef is a very suave and polite member of the Syrian consulate and is in their secret police. Was first seen in
- Ralph Carbone (Authentic Nick) - A dead body is found in one of the ovens in his pizza joint. Distantly related to the Spolano crime family, but that turns out to be irrelevant.
- Sal Malavolta (Terrific Authentic Nick) - Called in the Feds to investigate Ralph Carbone for mob connections.
- Luca Sabalini (Authentic Terrific Nick) - The night before the murder, Sabalini had a verbal fight with the victim over the ingredients in Sabalini's "fat-free" pizza.
- Vinnie Delfino (Terrific Nick) - Just another player in the pizza wars. All we know is that his pizza is delivered in black vans.
- Mike Royce, Beckett's former training officer last seen in Under the Gun, turns up dead in a New York alley while on the trail of an arms dealer, and Beckett flies out to L.A. to find his killer. Castle, of course, just happens to be going that way as well.
- Victor Baron (a Donald Trump character), runs the All-American Beauty Pageant and has cameras everywhere "because the public loves the underbelly"
- Kayla Baron ("Ivana Trump") was the winner of the pageant 15 years ago. Is upset that Victor had an affair, not because of the affair so much, but of who might have seen - and who she needs to be embarrassed around.
- Bobby Stark the star of "Family Foibles" who is narcissistic and is totally stoned during his interrogation (he sat down NEXT to Beckett). Beckett describes him as "a guy that's dropped more pills than a three-fingered pharmacist!"
- Candace Ford is the pageant director that had a one night stand with Bobby Stark, but is even more embarrassed because HE doesn't remember
- Miss Georgia Joy Jones stole Amber's violin hoping it would increase her chance of winning. She's desperate and says that this is her last chance at winning because "I'm 25, I'm OLD"