, born on September 23, 1959
, New Jersey
. His real name is Jay Scott Greenspan.
He is best known for his role as George Costanza on the long-running NBC sitcom Seinfeld. He also supplied the voice of the title character in the animated series Duckman. He has also starred in many Broadway musicals, and many movies.
He can currently be seen playing the role of Boris Badenov in the movie "The Adventures of Rocky and Bullwinkle".
He is married and has two sons.