* ActorAllusion: When the office workers mistake Phil's brother for Phil himself.
--> '''Everyone:''' ''"He's back! Phil's back! Phil's back!"''
--> '''Random Employee:''' ''"[[Creator/StephenColbert Stephen's]] back!"''
** [[FreezeFrameBonus A well timed pause]] will reveal a bus with an ad for ''Series/TheColbertReport'' [[spoiler:running over Phil]].
*** Before that, when Phil says he's leaving:
--> '''Phil Ken Sebben''': So, I got this tremendous opportunity! My own law firm! Might put my name in the title! Get a big S-shaped desk! Great for interviews! A spin-off, if you will!
--> '''Harvey:''' So... you're leaving us?
--> '''Phil Ken Sebben''': I wouldn't say that. I'll just be extremely busy on the [[TheColbertReport new show]], err, firm.
--> ''(Stephen Colbert himself can be seen in the elevator on the ride down, amongst Phil's luggage.)''
** Alluded to on Colbert's show as well, after pointing out that presidential candidate Mitt Romney had a nervous "ha ha" laugh that sounded similar to Sebben's. He even held up a copy of the DVD, and did the laugh live.
* AscendedFanon: A major joke of the series. The majority of Birdman's cases are based around popular fan theories (Doctor Quest and Race Bannon are actually a gay couple, the Scoobie gang are stoners,Top Cat is really a pimp, etc.) and headscratchers (why can't you see Apache Chief or Grape Apes genitals, despite their respective sizes?, why is Secret Squirrel apparently naked under his trench coat?, etc.) related to old Hanna Barbera cartoons.
** Creator/StephenColbert as Phil Ken Sebben and Reducto.
** Creator/LewisBlack as Elliott the Deadly Duplicator.
** [[BarneyMiller Detective Detrick]] has been demoted to Bailiff.
** Peter [=MacNicol=] ([[WesternAnimation/TheSpectacularSpiderMan Doctor Octopus]]) as X the Eliminator.
** Michael [=McKean=] as Spyro.
** Gary Cole ([[Film/OfficeSpace Lumbergh]]) plays Harvey himself (and Mightor).
** Birdgirl is voiced by [[Series/CriminalMinds Paget]] [[WesternAnimation/DanVs Brewster]] (who was also Ms Indestructible in ''Film/TheSpecials'')
** [[Series/TheAdventuresOfPeteAndPete Toby]] [[KingOfTheHill Huss]] played Ernie Devlin and Shado The Brain Thief.
** Music/GreyDelisle as Debby and various other characters.
** Creator/MauriceLaMarche as [[WesternAnimation/TheFlintstones Fred]], [[WesternAnimation/YogiBear Yogi]], QuickDrawMcgraw, WesternAnimation/SpeedBuggy, and others.
** Creator/TressMacNeille as Wilma and Pebbles
** TomKenny as [[WesternAnimation/YogiBear Boo Boo]] and WesternAnimation/TopCat
** In a case of RetroactiveRecognition for those who've yet to see this show, Mentok is [[WesternAnimation/TheLegendOfKorra Varrick]].
* ScheduleSlip: One of the main downfalls of the series. While the first season aired on schedule, the remaining episodes aired all over the place, with one or two airing then a gap of nearly a year before the next batch aired. Potentially mocked in "Turner Classic Birdman":
--> '''Robert Osbourne:''' You may have heard of the animated show ''Harvey Birdman: Attorney at Law''. In fact, if you're persistent, you can sometimes still catch it late at night on cable.