The 25 Best Seinfeld Characters Who Only Appeared In One Episode

"Seinfeld" is widely regarded as one of the greatest series of all time due to its distinctive comedic style and its memorable cast. From main players like the quick-tempered George Costanza and the oddball neighbor Kramer to supporting characters like the conniving Newman and the digression-prone Mr. Steinbrenner, there's no denying the show has one of the most remarkable collections of characters in sitcom history. By focusing on the many antics and misadventures these characters get into, "Seinfeld" quickly became one of the most popular series of its day, and continues to enjoy critical acclaim decades later. 

Given how many recurring characters fans see time and again on "Seinfeld," it's easy to forget how many smaller characters are sprinkled throughout the series. Sometimes, these characters are just as crazed and neurotic as Kramer and George. Other times, they're relatively normal people whose lives are practically ruined by their interactions with the main characters.

In many cases, these one-off characters are the highlights of the "Seinfeld" episode they appear in, proving themselves every bit as fun to watch as the main cast despite their limited screen time. Here are some of the best one-off characters to appear in the show's nine-season run.

A man employed at the tennis pro shop that Jerry occasionally visits, Milos comes across as an expert player whose knowledge and advice can make or break a player's game. Appearing in Season 8's "The Comeback," he encourages Jerry to buy an expensive racket, claiming it's the only one he uses. Later, Jerry happens to spot Milos — disguised via large sunglasses and a baseball cap — in the middle of a tennis game, demonstrating skills that are just plain awful, with Jerry describing Milos as "the worst tennis player" he's ever seen.

Trying to keep his poor tennis playing abilities a secret, Milos at first tries to coax his wife, Patty, into sleeping with Jerry to ensure his abysmally bad playing stays under wraps. After Patty refuses to do so and loses any respect she has for Milos, Milos begs Jerry to let him win a game to "prove himself a man" in front of his wife's eyes again. When Jerry agrees, Milos pushes his luck, insulting Jerry throughout the entire game in front of a group of onlookers, causing Jerry to snap and begin creaming Milos on the court.

Milos fits right in with the overall universe of "Seinfeld": a character whose pettiness and ineptitude are his undoing. 

Years before he was kickstarting the MCU or delivering "The Mandalorian" to "Star Wars" fans, Jon Favreau launched his career with roles on several prominent sitcoms of the 1990s, "Seinfeld" foremost among them. Appearing in Season 5's "The Fire," Favreau plays Eric the Clown, a party clown hired to entertain guests at a birthday party for the son of a woman George is dating at the time.

During the party, George gets into a heated argument with Eric due to Eric not knowing who Bozo the Clown is. Though Eric is patient and tries to engage in a reasonable discussion with George at first, he quickly tires of George's incessant ramblings, shutting him down with his impeccable delivery of the line, "You're living in the past, man. You're up on some clown from the '60s, man!" After George walks away, he notices smoke emanating from the kitchen, leading him to cause mass panic by yelling "Fire!" He then knocks down several women and children to get out of the building first. Meanwhile, the level-headed Eric stays behind, putting out the source of the fire (some overcooked burgers) with his large clown shoe before charging out in an attempt to attack George with the rest of the party guests.

An upstanding clown if ever there was one, Eric should've gotten a medal both for putting out the "fire" and for demonstrating considerable patience with George. An all-around good guy, his hilarious debate with George on Bozo has to be one of the highlights of Favreau's early work.

A man new to Manhattan with whom Jerry, George, and Kramer occasionally play basketball, Jimmy appears in the Season 6 episode "The Jimmy." An athlete who sells his own patented shoes, Jimmy has the unusual habit of referring to himself in the third person. This habit eventually leads to confusion when Elaine tries to see whether another gym attendee is interested in her. Jimmy tells her that "Jimmy is pretty sweet on you." After clearing up the confusion, they end up agreeing to go on a date, only for it to be ruined when the irate Jimmy attacks Kramer, who cost him a potentially lucrative venture with George by accidentally breaking Jimmy's leg.

Jimmy's odd vernacular is reason enough for him to make this list. Most people only talk about themselves in the third person as a joke (Kanye excepted), but Jimmy elevates it to an art form. It's all he knows. Every single sentence out of his mouth is "Jimmy this" or "Jimmy that." The first few times you hear it, it's strange. The next few times, it's annoying. But hearing him refer to himself as Jimmy in the middle of an argument, a fight, or as he's being dragged away by security — screaming "Hands off Jimmy! Don't touch Jimmy!" — becomes downright hilarious.

Plus, it's Jimmy we have to thank for George referring to himself in the third person in later seasons — a habit he picks up here, using it to get out of work-related trouble with Steinbrenner.

A man Elaine dates in Season 6's "The Race," Ned Isakoff is a stringent communist who suffers numerous hardships thanks to his unwavering loyalty to his beliefs. Elaine is originally thrilled with the novelty and excitement of his politics. Ned shows up throughout the episode to parody the difficulties faced by communists in America. When he finds Kramer having a hard time working at the local mall during the holiday season, Ned encourages him to read some literature on workers' rights and how they're being exploited by the upper classes, essentially converting Kramer to communism.

Later, Elaine tries to order food from a Chinese restaurant Ned's father used to frequent after being blacklisted. Problem is, Elaine previously got banned from the establishment for complaining about a botched delivery. When the driver finds out Elaine is the person behind the order, he blacklists Ned as well, claiming Elaine "named name," in a parallel to the 1950s Hollywood blacklist.

Many of Elaine's boyfriends have odd habits, but even by Elaine's standards, Ned seems exceptionally quirky. A deep believer in communism, he spends his time reading communist newspapers and ranting about the evils of capitalism to anyone who will listen. He even takes special care to look like a communist — his facial hair and glasses make him look like a mirror version of Trotsky and he dresses in drab olive clothing. He's not Elaine's best boyfriend, but he's one of the most unforgettable people she ever dated.

Another of Elaine's more noteworthy boyfriends, Alan Mercer is a famously bad "breaker upper" whom Elaine dates a handful of times in Season 8's "The Andrea Doria." Not much is known about him, save for the fact that practically every woman he dates ends up violently hating him after Alan personally insults them when their relationship ends. After Elaine tries to break her own relationship with Alan off, Alan childishly tells her she has a big head — in the literal sense — prompting her to feel humiliated and insecure afterward.

Towards the end of the episode, the two temporarily begin dating again, with Alan apologizing for his earlier remark, only to passingly joke about a small bump in Elaine's noise. Tired of his insults, Elaine physically attacks Alan in the middle of the restaurant they're dining in, stabbing him in the head with a fork.

Alan is likely among the worst men Elaine ever dated in "Seinfeld." He's rude, immature, and overly sensitive, taking all of his breakups far more personally than need be. It's still entertaining to see him mentally break down someone like Elaine with just a simple remark. It's no wonder why he was stabbed, beaten, and had hot coffee thrown on him by his various exes with an attitude like that.

A former college buddy of Jerry's, Seth makes his appearance in Season 8's "The Chicken Roaster." Happening upon Jerry on the sidewalk, Jerry invites Seth to lunch, encouraging him to blow off a meeting at work — a decision that costs Seth his career. Now unemployed, Seth finds a job as assistant manager at the Kenny Rogers Roasters that's just opened up across from Jerry and Kramer's apartment building.

You can't help but feel bad for Seth. From the moment he appears on screen, he just can't catch a break. He seems like a great guy — cheerfully going along with Jerry, even if it means putting his own job at risk — but is completely unable to find a decent footing in life, forever getting the short end of the stick. Like so many characters the main "Seinfeld" cast encounters, his life is practically ruined not once, but twice thanks to Jerry (who's also responsible for closing Kenny Rogers Roasters by introducing rat fur into the building).

Still, no matter how grim his situation becomes, Seth always seems to have a happy-go-lucky mindset and an optimistic attitude, telling Jerry, "The important thing is we got a chance to catch up" after he's fired, dwelling on the positive aspects in life in lieu of the bad. It's a personal outlook on life we can all take a page out of.

A high school classmate of George and Jerry's, Duncan Meyer appears in Season 6's "The Race" as the boss of a woman Jerry is dating. In the episode, it's established that Duncan was Jerry's former rival, having grown obsessive over the results of a race the two had in ninth grade that Duncan (correctly) believes Jerry cheated at in order to win. Over 20 years later, Duncan is still fuming at his loss, believing himself to be faster than Jerry and continuing to insist Jerry cheated in that fateful gym class years ago.

It's always interesting to see Jerry's enemies in "Seinfeld," especially one that dates as far back as high school. While Jerry and Duncan might not have the same frosty dynamic as Jerry and Newman, Duncan still makes for a supremely entertaining one-off villain out to ruin Jerry's reputation.

The highlight of his appearance in "The Race" comes when he challenges Jerry to rematch two decades after their original race, inviting all their former classmates and even threatening to fire Jerry's girlfriend should he refuse. Of course, Jerry ends up cheating again, gaining a healthy head start on Duncan before beating him once and for all. I's more than likely Duncan will continue to fume at Jerry's victory, telling anyone who will listen Jerry cheated not once, but twice in their races together.

Kramer has alluded to having a ton of friends outside the main characters of "Seinfeld" whom fans, Jerry, George, and Elaine never meet. One of the few friends Kramer fans do actually see is Brody, a shady criminal who runs an illegal bootlegging operation that produces and sells pirated films on the streets. Making his single episode appearance in Season 8's "The Little Kicks," Jerry becomes an unwitting accomplice to Brody's operation after Brody forces him to film the premiere of a film.

Impressed with Jerry's camerawork, the two begin working together more frequently, until Jerry's artistic demands grow too taxing, angering the already ill-tempered Brody. Their partnership undone, Brody physically threatens Jerry to deliver the tape of a film he was meant to shoot, then disappears once he's got the desired tape in his hands.

A guy with a very touchy side to his personality, Brody is a serious man who cares about one thing: making a buck off his films. Quick to anger, he doesn't take slights easily, threatening Jerry and Kramer repeatedly (even at gunpoint) if Jerry continues refusing to go along with his work. However, as Kramer points out, such unpredictability makes Brody a "fun" person to hang out with. We suppose it's true that there's never dull a moment when he's around.

There have been a number of characters who seem like mirror versions of George on "Seinfeld." Possibly the most striking resemblance comes in the form of Steven Koren, a high school student who applies to the Susan Ross Scholarship in Season 8's "The Van Buren Boys." A young man who appears identical to George in personality and appearance, Steven is a mediocre student with high aspirations whom George immediately sees as a younger version of himself. As George describes it, "With a little guidance, Steven Koren is going to be everything I claim to be, only for real."

Unfortunately, when Steven changes his mind about pursuing a career as an architect — George's lifelong dream job — and opts instead to become a city planner, George revokes his scholarship, feeling betrayed by the sudden career switch. Dejected and with no other options left, Steven joins the local Van Buren Boys gang in a bid to terrorize George into changing his mind and giving him his scholarship back.

Seeing George's doppelgängers is always good for a laugh. It's all the funnier seeing George talk to a junior version of himself. It's probably good that Steven's mentor relationship with George ended when it did, considering the kind of negative effect George has on the people he grows close to.

Lou Filerman has to be one of the simplest but funniest joke set-ups for any character on "Seinfeld." A new employee to the J. Peterman catalog in Season 9's "The Merv Griffin Show," he is known for quickly and silently moving through the halls of the workplace, sneaking up behind people without detection, much to Elaine's annoyance. "A real sidler," as she puts it, Lou goes around surprising everyone in the office, using his speed and silent footsteps to claim credit for work he hasn't completed.

To better announce his presence, Elaine tries convincing him to carry around a pack of Tic Tacs, much the same way you'd attach a bell to a cat. The incident backfires when Peterman blames Elaine for the incessant rattling, forcing her to ditch her Tic Tac plan and find another way to track Lou.

Compared to other "Seinfeld" minor characters, Lou doesn't have many lines or even that much screen presence in the only episode he's in. He makes do with that limited appearance, flashing that huge toothy grin and popping up behind characters like a horror movie villain. It's an ingenious concept for a one-off character, making Lou one of the better employees we see at the J. Peterman workplace.

Larry David can be heard throughout "Seinfeld," from recurring characters like Mr. Steinbrenner to the background voices played in numerous crowd scenes. He also has multiple on-screen cameos. One of his most underappreciated characters on "Seinfeld" has to be his role as Frank Costanza's lawyer, known only as "the man in the cape" or "the caped lawyer."

Making his brief appearance in Season 6's "The Chinese Woman," Elaine and Jerry spot the man in the cape with Frank in Manhattan. The pair wonders who the man is, why he's wearing a cape, and what Frank is doing with him (something that equally confounds George when they tell him about it). Later, Frank tells George that the man is his lawyer, explaining that he wears the cape because "[h]e's very independent. He doesn't follow the trends."

Seinfeld has had many unnamed characters during its nine-season run, but the man in the cape has to be the best. From his dramatic superhero stance while talking with Frank on the street, to the fact that he wears dark sunglasses even during the middle of the night, he's an absurd character about whom you're dying to know more. Even the fact that he introduces himself by saying "I'm Frank Costanza's lawyer" — as though his entire identity is built around being Frank's lawyer — is an ingenious concept that never stops being funny.

One of the more recognizable faces to guest star on "Seinfeld" came in Season 6's "The Scofflaw," which featured comedian Jon Lovitz playing Gary Fogel, a mutual friend of Jerry and George. At the start of the episode, George bumps into Gary, who reveals to him he is undergoing chemotherapy for cancer (something he also privately confided in Jerry months before). Later, though, Gary comes clean to George that he's actually been lying and that he never actually had cancer at all, but has been merely using the perks associated with the diagnosis — such as Jerry buying him an expensive, realistic wig — to his benefit, hiding the truth from him in the meantime.

It takes an especially horrible person to lie about having cancer. Still, Gary's inexcusable actions aren't completely that different from the main characters — George himself says he'd be probably do the same thing as Gary if it meant getting a great wig. For as awful as Gary is, he still is only slightly worse than the main characters.

Jon Lovitz has always been a great comedian to watch on any project and his comedic style meshes well with the overall tone of "Seinfeld." His ultra-confident personality, banter with George and Jerry, and over-the-top delivery of his signature catchphrase ("Good for you, Jack!") make him an incredibly entertaining addition to the "Seinfeld" universe. It's just a shame he meets his premature death off-screen via car accident after adjusting his toupee in traffic, as revealed in Season 6's "The Face Painter."