Well, to make a long story short, Jason Alexander is Jewish!
Since Jason Alexander's mother is Jewish, and in Orthodox Judaism and Conservative Judaism, those with a Jewish mother (or those who underwent a halakhic conversion) are considered Jewish, then that makes him Jewish. His father is Jewish too.
Jason Alexander (whose full birth name is Jay Scott Greenspan) was born on September 23, 1959 in Newark, New Jersey, U.S..
He is best known for his role as George Costanza on Seinfeld, appearing from 1989 to 1998.
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