* ActorAllusion:
** Michael Emerson saying "I've been watching you for a long time, John" sounds [[Series/{{Lost}} awfully familiar]].
** So does the sound of a receipt being printed in a taxi cab that just so happens to be driven by Michael's character. [[spoiler: LOST's sound effect for the "smoke monster" was derived from this sound.]]
--> Reese: "Where did you come from?"\\
Finch: "I breached the space/time continuum. Not really." [[Series/{{Lost}} (Yes, really).]]
** In "Witness," a student of the teacher John is protecting is reading ''The Count of Monte Cristo'' as a homework assignment. Jim Caviezel played the title count in the 2002 version of the movie.
*** Doubles as a WholePlotReference. ''The Count of Monte Cristo'' is about a man who devotes his life to revenge, heedless of the cost to others--which is a pretty fair description of [[spoiler: that episode's [=POI=], Carl Elias]].
** At one point Detective Carter tells Reese that he can't keep [[Film/ThePassionOfTheChrist playing God]].
** There are at least two scenes in "Judgement" where [[Film/ThePassionOfTheChrist Jim Caviezel]] is shown standing near [[WhatDoYouMeanItsNotSymbolic a statue of the Virgin Mary]].
** In episode 2.5 "Bury the Lede" Reese is given the alias "John Anderson." The surname "Anderson" is a derivative of [[Film/ThePassionOfTheChrist "Son of Man"]]
*** Judging from the number of [[Film/ThePassionOfTheChrist Passion Of The Christ]] references that have been made so far, it's likely that the list of Jesus jokes is only going to keep growing.
** Leon Tao just wants to get [[Series/{{Lost}} lost]].
** [[Film/DateNight This is not the first time Taraji P. Henson has played an NYPD cop investigating bent cops, chasing vigilantes]].
** In "Triggerman", Jonathan Tucker plays the POI, an Irish mobster who [[spoiler: [[TheAtoner regrets his life of crime because of love for a woman]]]]. [[Series/TheBlackDonnellys Sounds Familiar?]]
** This isn't the first time Jim Caviezel has heard someone with an English accent say [[Series/{{ThePrisoner}} "I'll be seeing you."]]
** It's also not the first time he has [[{{Frequency}} worked with a partner to use foreknowledge of violent crimes and tragic events to try to prevent them from happening.]]
** On that note, he's also sarcastically called [[{{Frequency}} "Chief" while pretending to be a cop]] in "Ghosts".
** Root [[spoiler:[[Creator/AmyAcker getting mistaken for a girl who disappeared from a library]]]]? [[Series/{{Angel}} That sounds familiar]].
** May be a coincidence but Root was initially believed to be [[spoiler: a girl who went missing from a library years earlier. Though it turned out to not be her,]] that particular backstory is not unlike another [[{{Series/Angel}} certain character]] portrayed by Creator/AmyAcker.
** Root also seems to have a thing for tasers, not unlike Fred.
** Inverted in ''Liberty''. The POI, Jack Salazar, is a member of the Navy who comes into conflict with Marines throughout the whole episode. He is played by Ray Valentin, who played Gabe Garza, a U.S. Marine, in GenerationKill.
** Creator/SaulRubinek plays a genius named Arthur who has ties to the U.S. government working on a secret project? [[Series/{{Warehouse13}} Hmmm...]]
* ActorSharedBackground:
** Like Jim Caviezel, Reese is from Washington state.
** Like Michael Emerson, Finch is from Iowa.
** In season 3 episode 18, ''Allegiance'', Shaw states that her mother was Iranian, making her half Iranian like Sarah Shahi, the actress portraying her.
* TheDanza: ''John'' Greer is played by ''John'' Nolan, though it's a moot point in that everyone uses LastNameBasis with him and the fact it's been confirmed to be an alias.
* ExecutiveMeddling: A positive case -- in the pilot's original script, Diane Hanson's exposure is only seen remotely. A scene was added in which Reese substitutes [[CaughtOnTape his recording]] of her talking to her dirty cops for evidence [[EngineeredPublicConfession she's presenting]] ''in court''.
* FanCommunityNicknames: "Irrelevants."
* FanNickname:
** "Team Machine", for the main characters once they're all on the same side.
** The gun closet in Reese's apartment is known as "The Closet of Mass Destruction".
** Strictly speaking, the titular POI is Reese. The characters calls the show's subjects "numbers". The fans call them [=POIs=].
* HeyItsThatGuy:
** [[ThePassionOfTheChrist Jesus Christ]] is ex-CIA, and [[{{Lost}} Benjamin Linus]] is a reclusive genius. TheyFightCrime!
*** In ''Person of Interest'', Jesus appears.
*** Actually, Jim Caviezel's role from 'ThePassionOfTheChrist'' is the subject of jokes on set. Both Taraji P. Henson and Caviezel himself mention it in the blooper reels.
** Detective Szymanski [[MichaelMcglone wants to save you 15% or more on car insurance]].
** Davidson in "Blue Code" ([=S01E15=]) is Reg E. Cathey from ''Series/SquareOneTV''.
** [[BigBad Elias]] still believes one should [[Film/GalaxyQuest "Never Give Up! Never Surrender!"]] Though it's more toward evil now.
*** Alternately, [[VeronicaMars Keith Mars]] went to the dark side when he left California.
*** Or maybe Sergeant Greg Parker go sick of saving lives and moved south.
** Root seems to have a habit of [[spoiler:[[Series/{{Angel}} going from meek and innocent ally to insanely badass villain]].]]
** [[Film/TeenageMutantNinjaTurtles April O'Neill]] shows up occasionally when our heroes need a little help.
** Officer Simmons of HR is Film/{{RoboCop|3}} - [[TheOtherDarrin but not the original...]]
*** Incidentally, the show arrived on Tuesdays at 10 at almost the exact same time one of its new [[Series/SonsOfAnarchy timeslot competitors]] cast [[Creator/PeterWeller the original]] Franchise/RoboCop as - wait for it - a (retired) corrupt cop.
** [[VideoGame/GrandTheftAutoV Trevor Phillips]] starts a fight at a bar full of sailors in "Liberty". No really, that's actually him.
*** In the same episode, [[PacificRim Herc Hansen]] is a dirty Force Recon Marine.
** Speaking of game characters, [[VideoGame/LANoire Cole Phelps]] is now a therapist in "The Perfect Mark".
** Two cast members from GenerationKill have appeared in Season Three:
*** Corporal Gabe Garza (Ray Valentin), appeared in ''Liberty''.
*** Evan "Rolling Stone" Wright (Lee Tergesen) appeared as Petersen, a [[CorruptCop member of HR]] in ''The Crossing''.
** [[TheUnit Charles Gray]] is a Cuban cab driver.
** [[Film/TheDarkKnight The Chechen]] is back as a hitman in "Ghosts".
* IKnewIt: A lot of fans suspected that [[spoiler: Carter's new partner was part of HR. "Reasonable Doubt" just about confirmed that.]]
** [[spoiler:As it turns out, so did she!]]
* PersonOfInterest is a virtual refuge for actors who’ve been in crime/urban dramas in recent years. Just to name a few;
** Detective Lionel Fusco, Reese’s (not so) DirtyCop lackey is [[Series/{{Brotherhood}} Freddie Cork]].
** Judge Gates is [[Series/BreakingBad Gale Boetticher]].
** [[Series/{{Brotherhood}} Speaker Donny Donatello]]/[[Series/TheSopranos Agent Harris]] makes an appearance in “The Fix.”
** Building superintendent Ernie Trask is [[Series/{{Dexter}} Angel Batista]].
** Simmons, a shady cop blackmailing Fusco for murder, is [[RescueMe Tommy Gavin]]’s brother, Mickey.
** In the episode “Identity Crisis,” Fusco helps [[TheWire Carver]] out on a case.
** [[Series/{{Castle}} Captain Montgomery]] is an ex-soldier who's running several crews of bank robbers.
** Elias’ father is [[{{Oz}} Antonio Nappa]]/[[Series/BreakingBad Hector Salamanca]].
** Elias himself is [[{{Series/Flashpoint}} Sgt. Greg Parker]].
** In “Matsya Nyaya,” Reese trains under [[TheWire Nick Sobotka]] when posing as part of an armored truck crew.
** Reese's ex-CIA partner Stanton is [[{{Series/LawAndOrder}} ADA Alexandra Borgia]].
** [[Series/TheWire Lester Freamon]] is a campaign manager and [[spoiler: the "big boss" of HR]].
** [[Series/TheOfficeUS Roy]] is a suburban father, hardware store owner, [[spoiler: and former safecracker]] in "The High Road."
** [[Series/TwentyFour Vladimir Bierko]] is a former MI6.
** [[Series/{{Supernatural}} The Devil]] is a publishing executive, and he and his wife mutually decided to have the other killed.
*** Hey, remember that time Jesus punched Lucifer in the face and threw him in the boot of his car?
** In "One Percent," one of the [[Series/ItsAlwaysSunnyInPhiladelphia McPoyle brothers]] cleans up to become a devil-may-care [[NoCelebritiesWereHarmed Not!]][[{{Facebook}} Mark]] [[Film/TheSocialNetwork Zuckerberg]].
** [[Series/FairlyLegal Kate Reed]] is a [[{{Determinator}} dedicated]] [[ProfessionalKiller counterterrorist operative]] on the run from her own agency. [[Series/BoardwalkEmpire Mickey Doyle]] is her former handler who [[WhatAnIdiot tries to take her down]].
*** Alternatively, [[{{Series/Life}} Reese]] is playing what promotional materials have described as a [[DistaffCounterpart female Reese]].
** This isn't the first time [[Series/FreaksAndGeeks Becky Ann Baker]] has been [[StormOfTheCentury stuck on an island during a storm]].
** [[{{Series/WhiteCollar}} Ellen]] moved to New Rochelle and was Jessica's mom.
** The [=ex-MI6=] agent opposing Reese is played by Julian Sands, who is better known to gamers as DeFalco, [[CallOfDutyBlackOps2 Raul Menendez's right hand man]].
*** Alternatively, Reese just foiled a plot by [[Series/StargateSG1 the Doci]].
** [[{{Supernatural}} Gordon Walker]] became a NYPD detective.
** [[Series/BoardwalkEmpire Frank Capone]] is a designer drugs distributor.
** [[{{Fringe}} Charlie Francis]] is now an estate investigator.
** There's also [[Film/TheDarkKnightSaga George Fredericks]], who's apparently turned evil after Film/TheDarkKnightRises.
* InvisibleAdvertising: The amount of advertising the show gets is woefully out of proportion with how high its ratings are; it's one of the highest rated shows in the country, let alone on CBS, and yet it's rarely advertised except on the night that it airs and it's often absent from the group CBS network promotions.
** The opposite was true when the show was first introduced. CBS promotions went into overdrive during the summer of 2011 to hype the show up, with POI ads outnumbering those for fellow rookie ''Series/{{Unforgettable}}'' by about two to one. Ironically, it had the opposite effect in the ratings - the premiere dropped nearly forty percent in 18-49 from the second half of a special hourlong episode of ''Series/TheBigBangTheory'' (5.1 to 3.1), and was outrated by all but two of CBS' other Monday-Thursday dramas. Given the pedigree and heavy marketing, this was considered a disappointing start. The only upside is that the show stayed in the general vicinity of this number for its entire run on Thursdays, while several other CBS shows fell off.
** Sadly, season three was moved to Tuesdays at 10pm, a budding curse slot for the network which has killed almost every show placed there since ''Series/JudgingAmy'' went off the air, and is down year-to-year. Facing ''Series/SonsOfAnarchy'', one of cable's most popular series, which has grown year-to-year for three straight seasons, isn't helping. Neither is the continuation of this trope in the new slot.
* MeanCharacterNiceActor: True, this can be said of anyone who isn't a serial killer but plays one, but there are some notables.
** Jim Caviezel, playing an AntiHero killing machine is a devout Catholic with two young children.
** Enrico_Colantoni playing affable but ruthless mob boss Elias is a spokesperson for the Tema Conter Memorial Trust, which helps first responders and such with post-traumatic stress disorder.
** Robert John Burke, playing the memorable and vile Patrick Simmons spent several days at Ground Zero after the September 11 attacks assisting with the search and rescue. He has since become a New York State certified firefighter. He also recently traveled to New Orleans to assist in the re-building of New Orleans fire houses.
* PlayingAgainstType: MichaelEmerson as Finch, who's almost the exact opposite of the manipulative [[Series/{{Lost}} Ben]].
** John Nolan's (who plays [[TheManBehindTheMan Greer]]) most notable movie role was [[Film/TheDarkKnightSaga George Fredericks]], a HonestCorporateExecutive and BenevolentBoss to the max. If you recognize him, it can be a little jarring to see him as a DiabolicalMastermind.
* RealLifeRelative: Carrie Preston, who plays Finch's former fiance, Grace, is MichaelEmerson's [[http://www.youtube.com/watch?v=kwFKN6CKwvo&feature=g-hist actual wife.]]
** [[JamesCarpinello Joey Durban]] is the real life husband of [[Creator/AmyAcker Root]].
** John Nolan [[spoiler:who played Kara's employer in "Dead Reckoning"]] is the uncle of Jonathan Nolan.
** Paul Sparks (Wilson in "Relevance") is married to Annie Parisse (Kara Stanton).
* ThrowItIn: Reese kissing Carter at the end of "The Crossing" was improvised by Jim Caviezel.
* WhatMightHaveBeen: The original script for the Pilot episode revealed all of John and Jessica's backstory in that episode, and would have also included a scene where Finch provides Reese with an apartment to live in. The John/Jessica backstory was cut down and then spread out over the course of the first season, and the apartment became a birthday gift in "Many Happy Returns".
** Carter's pursuit of Reese was originally intended to continue over the course of the whole first season, but she ended up joining the team mid-way through due to [[ExecutiveMeddling pressure from CBS]].[[note]]Mileage Varies on whether or not it was a good move for her to join so soon.[[/note]]
* WhyFandomCantHaveNiceThings: The reaction to the ending of "The Crossing" has forced the show runners and [[spoiler: Taraji P. Henson]] to go into something akin to damage control mode.
--> '''Taraji P. Henson:''' "That's why people are so distraught today. And that's what art is supposed to do: It's supposed to make you feel. You're supposed to be mad and want to throw a glass and yell, "Goddammit, I'm not going to watch this show again." We did our job."
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!!Miscellaneous Trivia:
* Jim Caviezel is ambidextrous in real life.
* While on location in New York City, Jim Caviezel saw some punk beating his girlfriend and "intervened".
** An incident which has caused some fans to come to the conclusion that he ''is'' John Reese.
* The (stolen) black Porsche that Reese drives in "Bury the Lede" actually belongs to Jim Caviezel.
** Which incidentally implies that John Reese stole Jim Caviezel's car.
* In the episode "Critical" ''Series/PersonOfInterest'' became one of the first mainstream US dramas to portray a ''married'' same-sex couple.
* Kara Stanton was killed off earlier than expected because Annie Parisse is already on ''Series/TheFollowing''. Ironically, her ''Following'' character, Debra Parker, was dead by the end of season one.
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