Jay Scott Greenspan, known professionally as
Jason Alexander, is an American actor and comedian. Over the course of his career he has received an Emmy Award and a Tony Award as well as nominations for four Golden Globe Awards. He gained stardom for his role as George Costanza in the NBC sitcom
Seinfeld (1989â1998), for which he won a Screen Actors Guild Award for Outstanding Performance by a Male Actor in a Comedy Series and was nominated for seven consecutive Primetime Emmy Awards for Outstanding Supporting Actor in a Comedy Series and four Golden Globe Awards for Best Supporting Actor in Television.