->''"The greatest part of the job was... that was for nine years it was a pleasure to go to work."''
-->--'''Jason Alexander''', summing up his time on ''Seinfeld''

Jason Scott Greenspan, otherwise known as [[StageName Jason Alexander]] (born September 23, 1959) is an American actor known to the world as the one and only George Costanza from ''Series/{{Seinfeld}}''.

In actuality, the man is an accomplished performer on the stage, having won a Tony Award for his singing contributions. However, it would be his role as George Costanza, {{Jerkass}} extraordinaire and [[HeterosexualLifePartners best]] [[NotThatTheresAnythingWrongWithThat friend]] to main character Jerry Seinfeld that would make Alexander a true household name. Being named "the greatest sitcom character of all time" by none other than Creator/RickyGervais, Alexander's accolades for the role included Emmy and Golden Globe nominations, as well as a win at the Screen Actors Guild Awards. One could say that, along with Michael Richards as Kramer, he became a BreakoutCharacter on the show.

His son Gabriel Greenspan is also an accomplished actor.

He's also an expert poker player.

!!His Credits include:
* Film:
** ''Film/TheMosquitoCoast'' (1986) as a Clerk
** ''Film/PrettyWoman'' (1990) as Philip Stuckey
** ''Film/JacobsLadder'' (1990) as Geary
** ''Film/{{Coneheads}}'' (1993) as Larry Farber
** ''Disney/AladdinTheReturnOfJafar'' (1994) as the voice of Abis Mal
** ''Film/{{North}}'' (1994) as North's father
** ''Film/DunstonChecksIn'' (1996) as the dad and hotel manager
** ''Disney/TheHunchbackOfNotreDame'' (1996) as the voice of Hugo
** ''Film/ShallowHal'' (2001) as Mauricio Wilson

* TV:
** ''Series/{{Seinfeld}}'' (1990-1998) as George Costanza
** ''WesternAnimation/AladdinTheSeries'' (1994-1995) as the voice of Abis Mal
** ''WesternAnimation/{{Duckman}}'' (1994-1997) as the voice of Duckman
** ''WesternAnimation/{{Dilbert}}'' (1999-2000) as the voice of Catbert
** ''Series/CurbYourEnthusiasm'' (2001, 2009) as himself
** ''Listen Up'' (2004-2005) as Tony Kleinman
** ''Series/EverybodyHatesChris'' (2006-2007) as Principal Edwards

!!Tropes associated with Jason include:
%%* BaldOfAwesome
* TheCastShowoff: Inverted. If you'd only watched ''Seinfeld'', You'd never guess he was a trained singer from George's flat, monotone vocals. He would later play it straight when he guest-starred in the MusicalEpisode of ''Series/{{Community}}''.
* RealLife/MeanCharacterNiceActor: Compared to [[{{Jerkass}} George]] [[ButtMonkey Costanza]], the man is quite considerate.
* NiceGuy: [[http://www.newsfromme.com/2013/05/01/the-power-of-fame This story]] as told by Creator/MarkEvanier describes Jason visiting an amateur musical and going out of his way to personally compliment everyone in the cast -- making sure to do it while their friends and family were around.
%%* NiceJewishBoy
* StarMakingRole: Again, while he was more than a respectable actor beforehand, ''Seinfeld'' offered him his greatest exposure. He's grateful for it too, because he's remarked that, otherwise, "he'd be remembered as that guy [[Film/PrettyWoman who tried to rape]] Creator/JuliaRoberts".
* TwoFirstNames: His StageName, Jason Alexander.