George is neurotic, self-loathing, and dominated by his parents, Frank and Estelle. He has been best friends with Jerry Seinfeld since their middle school years.
George exhibits a number of negative character traits, among them stinginess, dishonesty, insecurity, and neurosis. Many of these traits form the basis for his involvement in various plots, schemes, and awkward social encounters. Episode plots frequently feature George manufacturing elaborate deceptions at work or in his relationships in order to gain or maintain some small or imagined advantage. George appears in every single episode except for "The Pen" in the third season.
His relationships with women are always unsuccessful. His most disastrous relationship, an engagement to Susan Ross, is one of the few that ends "well" for George; he fears marriage and Susan's unexpected death saves him from the commitment. However, even this comes back to "bite him in the butt" — her parents create a foundation in her honor and endow it with the land, mansions, and money that George might have inherited.
Although occasionally referred to as being dumb by his friends (notably Elaine), a contention George does not really argue with, there is every reason to believe George is quite an intelligent man despite his neurotic behavior. He is considered an expert liar, and is often able to talk his way out of extraordinary situations. His skeptical, almost paranoid nature also makes it extremely difficult for someone to put one over on him. In one episode, it is discovered George has what would appear to be genius-level intelligence but that he can never access it because his mind is always so completely focused on sex. When circumstances allow him to temporarily remove sex from his mind, he is able to reach his true potential.
George is based primarily upon co-creator Larry David (see 5th Season DVD Special Feature "Jason + Larry = George"), and named after Jerry Seinfeld's college classmate Michael Costanza (who appeared in the 3rd Season episode "The Parking Space"). Many of George's predicaments were based on past real-life experiences of David. In "The Revenge", for example, when George quits his job in a fury only to realize his actions were a mistake, he goes back the next day as if nothing happened, mirroring David's actions while working as a writer for Saturday Night Live, when he quit and then returned to his job in the same manner.
Alexander, from his first audition for the part, based the character George on Woody Allen. As the show progressed, Alexander discovered that the character was based on David. As Alexander explains in an interview for the Seinfeld DVD, during an early conversation with David, Alexander questioned a script, saying, "This could never happen to anyone, and even if it did, no human being would react like this." David replied, "What do you mean? This happened to me once, and this is exactly how I reacted!"
George has shown on several occasions that he is extremely afraid of contracting lupus. Costanza shows his distress about it in "The Heart Attack" when the doctor notifies that there is indeed something wrong with him. He shows his distress once again in "The Suicide" when a mystic teller tells George not to take his vacation to the
