The television show Seinfeld was known for featuring many characters, each with their own special characteristics.
|#||Character||# of episodes||Primary actor||Character description|
|1||Ruthie Cohen||101||Ruth Cohen||Cashier at Monk's Cafe|
|2||Newman||47||Wayne Knight||U.S. Postal Worker. Associate in many of Kramer's get rich quick schemes.|
|3||Frank Costanza||29||Jerry Stiller||Eccentric and very quick to anger.|
|4||Estelle Costanza||28||Estelle Harris||George's obnoxious and melodramatic mother. Constantly questions Frank and George's actions.|
|5||Susan Ross||28||Heidi Swedberg||George's fiancée. Daughter to wealthy parents and former NBC executive. Briefly experimented with Lesbianism. Died licking poisonous wedding invitation envelopes.|
|6||Morty Seinfeld||22||Barney Martin||Jerry's father. Has strong convictions. Fittingly, he spent some time as politician in his Florida retirement community.|
|7||Helen Seinfeld||22||Liz Sheridan||Jerry's mother. Often needed to provide reason to Jerry and Morty's eccentric lifestyle.|
|8||J. Peterman||21||John O'Hurley||Elaine's boss. Eccentric owner of the fashion oriented J. Peterman catalog.|
|9||George Steinbrenner||16|| Larry David|
Mitch Mitchell, Lee Bear
|George's boss. Depicted as a rambling, hard-nosed owner of the New York Yankees. His face is never shown. He seems to live in his own little world.|
|10||Uncle Leo||15||Len Lesser||Jerry's uncle. Brother to Helen Seinfeld. Somewhat of an old coot.|
|11||David Puddy||11||Patrick Warburton||Elaine's on again off again boyfriend. Phased and calm, yet can be a surprisingly passionate individual at times. Somewhat of an airhead. Used to be an auto mechanic but later became a car salesman.|
|12||Mr. Wilhelm||11||Richard Herd||George's supervisor. Works hard to ensure the Yankees organization runs smoothly.|
|13||Mr. Lippman||11||Richard Fancy||Elaine's boss. Owner of Pendant Publishing. Later gave up that position and opened up a bakery that sold only the tops of muffins.|
|14||Mr. Pitt||8||Ian Abercrombie||Elaine's boss. Extremely wealthy business owner. He is a very picky individual and is nearly impossible to please.|
|15||Mickey Abbott||7||Danny Woodburn||Little actor. Close ties with his friend Kramer.|
|16||Dugan||6||Joseph Urla||Elaine's co-worker.|
|17||Jackie Chiles||6||Phil Morris||Kramer's eccentric lawyer. A very successful lawyer, but has had bad luck when representing Kramer.|
|18||Kenny Bania||6||Steve Hytner||Stand-up comedian. Not particularly good at his job. Jerry especially dislikes him because he uses Jerry's act to warm up his audience.|
|19||Jack Klompus||4||Sandy Baron||Short tempered resident of Phase Two of the Pines of Mar Gables who seems to consistently have a grudge against Morty Seinfeld. Has a cool astronaut pen that he gives to Jerry out of duress. Gets a "sweetheart deal" from Jerry for Morty's Cadillac, then subsequently drives it into a marsh.|
Characters appearing in 5 or more episodes
- Newman (played by Wayne Knight): Jerry and Kramer's vengeful and spasmodic neighbor, this character only appeared from 1992 onwards. Originally conceived to be "the son of the landlord [who] 'tells' on everyone", Newman evolved as the series progressed into a scheming mailman who was friends with Kramer but nursed a grudge against Jerry. During Season 2 only his voice was heard. An example of this is when he annoys Kramer by claiming that he's planning to commit suicide. Originally, Larry David did some of the voice work for Newman before the character was fully developed. In subsequent reworkings of the early episodes his voice was re-dubbed with Wayne Knight's. While Newman was portrayed as Jerry's arch-nemesis he remained close friends with Kramer. Jerry has described Newman as "pure evil" and always greets him with "Hello... Newman" in a sarcastic, disgusted tone.
- Frank Costanza (played by Jerry Stiller, The King of Queens) and Estelle Costanza (played by Estelle Harris): doting parents of George, who live in Queens.
- Susan Ross (played by Heidi Swedberg): ex-fiancée of George, dies from toxic wedding invitation envelope adhesive. She was a former executive at NBC when Jerry and George were pitching Jerry. After her death, George is roped into being a trustee for her memorial charity foundation. Susan hates Kramer for various reasons: In one episode, he drinks some bad milk and throws up on her; in another, Kramer burns down her father's cabin; and in the last episode in which Susan was alive, Kramer forgets her name (he calls her "Lily").
- Helen Seinfeld (played by Liz Sheridan): Jerry's mom. She adores Jerry and often asks rhetorically, "How could anyone not like him?"
- Morty Seinfeld (played by Barney Martin): Jerry's dad. He sold raincoats for 35 years. He hates Velcro—he can't stand the tearing sound. He was also impeached as Del Boca Vista president when the other board members accuse him of stealing funds to pay for a new Cadillac—even though Jerry actually bought the car for him. The other residents don't think Jerry has that kind of money, either.
- Jacopo Peterman (played by John O'Hurley, To Tell the Truth): based on a real person; the eccentric and loquacious boss of Elaine Benes. He has a long, interesting history that includes opium addiction. When Peterman decides to write an autobiography, Kramer tries to sell his stories to him. Later on, Kramer claims himself to be "the real Peterman," and starts a reality bus tour, a parody of Kenny Kramer's "Reality Tour".
- George Steinbrenner (voiced by Larry David, Curb Your Enthusiasm): George Costanza's boss while working for the Yankees; his face is never shown.
- Uncle Leo (played by Len Lesser): Jerry's unavoidable and annoying uncle who always greets Jerry with a hearty "Jerry, hello!" His son Jeffrey, of whom Leo is very proud, works for the Parks Department.
- David Puddy (played by Patrick Warburton, The Tick): on-again, off-again, sometimes "religious", boyfriend of Elaine Benes. He wore an 8-ball jacket and enjoyed giving high fives while working as a salesman in a Saab dealership. Also a hardcore New Jersey Devils fan with a known affinity for Arby's. Known for his squinting, staring, generally laid back, passive, attitude, and his deadpan delivery (except with bursts of adrenaline like during the hockey playoffs). His most common line: "Yeah, that's right."
- Mr. Wilhelm (played by Richard Herd): George's superior at the New York Yankees; also George's brainwashed maid (Tanya) with the Sunshine Carpet Cleaners.
- Mr. Lippman (played by Richard Fancy): Elaine Benes' boss at Pendant Publishing. Briefly hired and fired George over inappropriate relations in his office with the cleaning lady.
- Justin Pitt (played by Ian Abercrombie): hired Elaine to tend to his personal needs, such as buying socks. Elaine lost her job with him when his intimates suspected her of planning his demise in order to secure an unusual employer-to-employee inheritance. He planned to "annex Poland by the Spring."
- Mickey Abbott (played by Danny Woodburn): a little person who took various acting gigs with Kramer. He considers bacterial meningitis the Hamlet of diseases.
- Dugan (played by Joe Urla): plays a minor role as a coworker of Elaine's.
- Jackie Chiles (played by Phil Morris, Wanda at Large): Kramer's erstwhile lawyer, an obvious parody of O.J. Simpson trial lawyer Johnnie Cochran. He's known for using a trio of exclamations in a single sentence. Jackie Chiles even had a life past the continuation of the TV series: Phil Morris appeared as the character in a few television advertisements.
- Kenny Bania (played by Steve Hytner): an unfunny stand-up comedian who has routines on chocolate drink mixes such as Bosco and Ovaltine. Jerry contributed some material to Bania's Ovaltine routine. He likes to eat at Mendy's. George feels he is the voice of a new generation, his generation.
- Dr. Tim Whatley (played by Bryan Cranston, Malcolm in the Middle): a dentist who converted to Judaism for the jokes. May be a molester; and possibly has sexual relations with his nurses. He is most certainly a dental assistant swapper. He is also a known re-gifter. He believes Jerry is a trouble maker (comparable to Woody Woodpecker).
- Larry the Cook (played by Lawrence Mandley): the Owner/Manager/Cook at Monk's Diner
- Mr. and Mrs. Ross (played by Warren Frost and Grace Zabriskie): Parents of George's fiancée, Susan. After Kramer burned down the family's cabin, it was revealed that Mr. Ross had had a homosexual affair with John Cheever. "Yes, he was the most wonderful person I've ever known. And I love him deeply! In a way you could never understand." (Season 4, "The Cheever Letters")
- Russell Dalrymple (played by Bob Balaban): NBC president; interviews Jerry and George for their pilot. He developed a significant crush on Elaine, which prompted him to join Greenpeace in an attempt to impress her.
- Norman Brenner appeared in minor parts in over 30 episodes. He was also Michael Richards' stand-in for all 9 seasons. His speaking roles included 'Ian' in "The Wig Master", 'Man at Airport' in "The Limo", 'Rider #4' in "The Muffin Tops", and 'Passerby' (with Buford the dog) in "The Doodle". He is noted on the Seinfeld DVDs under "Notes About Nothing" with the words "WHERE'S NORMAN?" showing on the screen just before he appears. All of his appearances are documented on the website www.wheresnorman.com. 
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