Newman!
Everyone has a Lex Luthor, and Newman was Jerry's. Although the ponderous postman scarfed muffin stumps and spread fleas, "he thinks of himself as quite princely," says actor Wayne Knight.

J. Peterman
"Ah, Elaine! This dry air is curing me like a Black Forest ham!" exulted J. Peterman, potentate of preposterous locutions. Acting with Seinfeld's fab four, says John O'Hurley, who played Elaine's catalog publisher boss, "was like being a studio musician with the Beatles."

The Marble Rye Lady
"I get a lot of 'Oh, you're the Marble Rye lady!' " says Frances Bay, who had her loaf snatched by Jerry in a '96 episode. "And I don't even eat rye bread!" Even her rabbi has been known to make a special effort to say hello, says Bay, "and he's got a really big congregation."

Chinese Restaurant Owner
"I thought the humor was really strange," says James Hong, the movie veteran (400 films in 45 years) whose character kept Jerry and company waiting eternally for a table. "But the director said, 'That doesn't matter. Just go with it,' and he was right. The show was nonsense making sense."

Crazy Joe Davola
He hounded Jerry while dressed as Pagliacci and stalked Elaine, who maced him with cherry Binaca. "Joe," says actor Peter Crombie, "still hasn't gotten his medication quite right."

Sue Ellen Mischke
Elaine's nemesis, Sue Ellen was the supporting character who lacked support—until Elaine bought her a bra. A teen rival once hung up actress Brenda Strong's bra in front of their class. "This made up for that," she says of her role. "It's bra karma."

Uncle Leo
Len Lesser credits Larry David with helping him nail Jerry's nutty uncle. "He kept telling me, 'More expansive!' " says Lesser, who in his 52-year career had never been in a sitcom. "I was worried about making a complete fool of myself, but I finally got it."

Susan
George's doomed fiancée took a licking and abruptly stopped ticking. "I still lick envelopes," says actress Heidi Swedberg. "It's the paper cuts I worry about, not the poisoning."

Kenny Bania
Wild about everything—from soup ("It's the best, Jerry! The best!") to a comedy routine based on Ovaltine ("That's gold!")—Bania defined pest. Comic Steve Hytner defines persistent: He auditioned for four other roles before landing Kenny.

Ruthie
Cast as a patron at Monk's, Ruthie Cohen was told by Larry David that she "moved like a cashier." Promptly counter-fitted, she stood behind the register in almost every show.

George Steinbrenner
Viewers saw only the back of his noggin, and Larry David actually spoke the character's lines. So why was Lee Bear cast as George's crazy boss? "I guess I was the guy with the biggest head," says Bear.

Mr. Pitt
An L.A. waiter once served actor Ian Abercrombie (Elaine's persnickety boss)a Snickers. Without missing a beat, he ate it "with a knife and fork."

Puddy
"He's earnest, but I wouldn't want to spend more than three minutes in an elevator with him," says Patrick Warburton of Elaine's fur-wearing, high-fiving beau.

Babu Bhatt
Well-meaning Jerry got him deported, prompting Babu to swear vengeance ("You very bad man!"). When Brit actor Brian George applied for a green card in real life, he says, "[INS officials] insisted they'd never deport Babu."