Fall 2002: Set to teach acting on the faculty of the University of Southern California as the first-ever George Burns Distinguished Visiting Professor in Performance.

Not only took the last name "Alexander" because of his father's first name, but it also helped him in auditions since the call backs were done in alphabetical order and thus he knew immediately if he was still in the running, or not, for parts.

Says he took on the role of Duckman because Duckman was "the anti George Costanza".

4/30/06: Debuted as a "professional magician" at the Magic Castle in Los Angeles. His act is based on studying and predicting behavioral patterns with his subjects.

The only of the four main actors (Michael Richards, Jerry Seinfeld and Julia Louis-Dreyfus) from "Seinfeld" (1990) not to win an Emmy for their work on the show

Has an extensive knowledge of the original "Star Trek" (1966) episodes and had aced a series of skill testing questions about the show on "Howard Stern" (1994)'s radio show. However, that "backfired" on his "Bob Patterson" (2001) ABC-TV series when William Shatner guest starred on an episode and Bob Patterson (Alexander) is traumatized.

Parents Ruth and Alex Greenspan; half-sister Karen Van Horn, half-brother Michael Greenspan.

Being a great fan of "Star Trek" (1966), he was finally given the opportunity to play a "Trek" role himself in 1999: he played the character "Kurros" in the "Star Trek: Voyager" (1995) episode "Think Tank". That same year, he was the host for the "Star Trek Viewers' Choice" VHS, notably for his Capt. Kirk impersonations.

2005: Celebrity Judge for UCLA Spring Sing.

Beat out Danny DeVito, Steve Buscemi, and Nathan Lane for the role of "George" in Seinfeld(1990).

While filming "Seinfeld" (1990), was always fitted with a suit one size too small, to make his character look "uncool"

One year for his birthday, his friends took him to a diner. They told him to close his eyes. When he opened them, William Shatner, aka Captain James T. Kirk, was in front of him. Captain Kirk was Jason`s childhood hero.

Started losing his hair at the age of 16.

Two children (Gabriel, born August 1991, and Noah, born February 1996)

Attended Boston University and left a year early because he was able to find acting work in New York City during the summer before his senior year. Later given an honorary degree.

1989: Appeared on Broadway in Jerome Robbins` musical "Broadway", for which he won a Tony award.

High school acting credits include the shows "Guys and Dolls", "The Odd Couple" and "Oliver".

Played flute and also percussion in the Livingston Lancer`s Marching Band.

Was a 1977 graduate of Livingston High School in Livingston, New Jersey. One of his classmates was Julia Montgomery. They co-starred in numerous high school productions.