* ActorAllusion:
** After what Gambol went through with the Joker, Michael Jai White still hates [[Film/{{Spawn}} clowns.]]
** Nestor Carbonell who played Mayor Garcia also played Batmanuel in ''Series/TheTick''.
* AllStarCast: Specifically Christian Bale, Michael Caine, Heath Ledger, Gary Oldman, Aaron Eckhart, and Morgan Freeman. Multi-decade spanning name recognition? Check. Critical acclaim? Check. [[RuleOfThree Awards cache]]? Check and the mate.
* BeamMeUpScotty:
** SelfDemonstrating/TheJoker is often mis-quoted as asking "Do I look like a man with a plan?" when Harvey Dent says that [[spoiler: his (Harvey's) disfigurement and the death of Rachel Dawes]] was part of his (the Joker's) plan, most likely because people associate the rhyming words "man" and "plan". The quote is actually "Do I really look like a guy with a plan?"
** "Why so serious?" isn't really the Joker's catchphrase. He only says the phrase in a fierce tone when pretending to be his dad, and the one time he says it as himself he says it almost sarcastically.
* DevelopmentGag: When Fox is asked for improvements to the Batsuit, he remarks, "You want to be able to turn your head." Prior to the Dark Knight Trilogy, no physical implementation of the Batsuit allowed the actors to turn their heads.
* DirectedByCastMember: Heath Ledger directed and shot the two home videos the Joker sends to the media (both the one where he tortures and kills the fake Batman, then the one where a captive Mike Engel is forced to read a script of the Joker's demands).
* FatalMethodActing: While Heath Ledger is not an example (he died after his parts were done), the stuntman who crashed the Batmobile during pre-production is.
* HeyItsThatGuy:
** Gambol is only bitter because he has [[Film/{{Spawn}} a bad history with clowns]].
*** Alternatively, The Joker just killed Film/BlackDynamite.
** Joker should watch out. One of the cops he holds hostage is [[VideoGame/MassEffect2 Harbinger]].
** [[Creator/HeathLedger The Joker]] [[BrokebackMountain just can't quit you]].
** William Fichtner's cameo as the bank manager.
** The ScaryBlackMan on the ferry at the end is [[Film/{{Friday}} Deebo]].
** Mike Engel was once a rookie cop who [[Film/AGnomeNamedGnorm teamed up with a gnome]] in order to solve a botched sting operation gone wrong.
** Eric Roberts ([[Series/DoctorWho The Master]]) is Sal Maroni.
** [[KeithSzarabajka Detective Stephens]] is [[Series/{{Angel}} Holtz]].
** Look carefully at the cops in the convict ferry. One of them is the original [[Series/{{Torchwood}} Jack Harkness]].
*** And [[SidAndNancy Sid Vicious]].
** Does that old guy who says "We are not intimidated by thugs" to The Joker look familiar to any Vermonters? He should because its [[http://en.wikipedia.org/wiki/Patrick_Leahy US Senator Patrick Leahy (D-VT)]], a lifelong Batman fan who also provided a voice in the ''WesternAnimation/BatmanTheAnimatedSeries'' episode "Showdown".
** Fans of old-school Franchise/MortalKombat oughta look closely in the background of the scene where Maroni and the Chechen are eating. Richard Divizio, AKA [[MortalKombat Kano]] and [[VideoGame/MortalKombat2 Baraka]] is an extra in that scene.
** Wuertz is [[Film/TheFugitive Chicago Police Department Detective Kelly]].
** One of the passengers on the civilian ferry was [[Series/BandOfBrothers once a member of Easy Company]].
** Looks like [[Series/TheTick Bat Manuel]] gave up on being a superhero and successfully ran for Mayor of Gotham City.
* HeyItsThatVoice:
** [[KeithSzarabajka Detective Stevens]] is [[Franchise/MassEffect Harbinger]] and [[Film/{{Transformers}} Laserbeak]].
** Sal Maroni is [[WesternAnimation/DannyPhantom Dark Danny]] and [[WesternAnimation/JusticeLeague Mongul]].
** One of the S.W.A.T. officers is [[VideoGame/KnightsOfTheOldRepublic Atton Rand]].
* MethodActing: To prepare for the part of the Joker, Heath Ledger spent six weeks in a motel room in seclusion to delve deep into his intended portrayal of the Joker's psychology.
* MythologyGag: A memorable line from the 1989 ''{{Film/Batman}}'' movie is the Joker's remark that he wants "his face on the one-dollar bill." In ''Dark Knight'''s viral marketing campaign, [[http://asmith50.files.wordpress.com/2008/07/jokerdollar.jpg Joker really did put his face on the one-dollar bill]]!
* TheOtherDarrin: Maggie Gyllenhaal as Rachel Dawes in ''Dark Knight'', replacing Katie Holmes from ''Begins''.
* PlayingAgainstType: One of the reasons people were so skeptical about Creator/HeathLedger playing SelfDemonstrating/TheJoker was that he wasn't known for villainous roles, let alone one of the most psychotic and monstrous characters in fiction, usually playing romantic leads. As we can see from the result, TropesAreNotBad.
* RealitySubtext: Bruce Wayne requesting a new Batsuit from Fox so that he can turn his head and be more agile, was the result of Christian Bale complaining about these problems with his Batsuit from the first movie.
* RecursiveAdaptation: Elements of Ledger's Joker were incorporated into the comics, most notably the scars. There may have been an abortive attempt to make him closer still, with someone drawing a line at killing Harley.
* ThrowItIn:
** SelfDemonstrating/TheJoker's SarcasticClapping when Gordon gets promoted wasn't in the script.
** While the scene when SelfDemonstrating/TheJoker blows up the hospital and the explosions suddenly stop, and Heath begins messing around with the detonator until the explosions suddenly start up again was initially credited to his ad-libbing, Christopher Nolan actually wanted [[http://www.starpulse.com/news/Casey_Johnson/2012/07/20/10_things_you_might_not_know_about_bat "a delayed, staggered explosive effect"]] in that scene. Considering that explosion scenes are usually filmed with extreme caution, ad-libbing would not have been allowed in this case.
** A lot of the Joker's mannerisms were developed when Heath Ledger was getting his makeup done, and would scrunch up his face to create different textures for the makeup. The creepy way in which the Joker sucks on his cheeks was one of these.
* TypeCasting: Ron Dean playing Mike Wuertz, one of Gordon's detectives. He behaves similarly to his performance as Detective Kelly in ''Film/TheFugitive''.
* WhatCouldHaveBeen: There's some fairly creepy concept art of the Joker before Heath Ledger was cast.

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