To say that you can count on one hand the number of good sitcoms of the last 15 years is an understatement; one finger is more than enough. But we will not sing the praises of "Seinfeld", a sitcom created by Jews and starring Jews, we will sing the praises of its most likable and, at the same time, hateable character.
George Costanza's ethnicity wasn't exactly covert; his last name is Italian, his father an Italian Catholic. The mother, however, couldn't be anything but Jewish, according to the show's creators.
And honestly, could George himself be anything but Jewish? Jason Alexander originally played his character as a take on Woody Allen. He later found out that co-creator Larry David wrote the character based on himself, so as the seasons went on, George became less Woody and more Larry... Trading one Jew for another. In fact, even with George's last name, one would be hard pressed to find a more stereotypical fictional Jew on television; neurotic, self-obsessed, besieged by his mother...
And a big fan of pastrami sandwiches.