Doug, Kramers COP BUDDY featured in (The Frogger). Kramer finds caution tape in the evidence room while the cops are worried about "The Lopper".
Cousin Jeffrey, Jerry's horse-faced cousin, about whom Uncle Leo always raves. He worked for the New York City Department of Parks and Recreation. Jeffrey once got Jerry tickets to a Paul Simon concert, and a glasses-less George once claimed to see Jeffrey kissing Jerry's girlfriend in the street (it turned out to be a policewoman patting a horse). According to Uncle Leo, Jeffrey's favorite animal is the leopard because he likes the spots, and he keeps in close contact with his college botany professor, a friendship which Leo thinks is rare. Jeffrey received a citation from the city for his edible foliage tour through Central Park. The back of Cousin Jeffrey's head can be seen in the deleted scenes for the policewoman/horse episode on the season DVD.
Bob Sacamano, one of Kramer's best friends, who is often referred to as the source of nutty ideas or inaccurate information. He is from New Jersey. Bob's father lives in Florida and is the source of faulty electronic organizers known as "Willards" (instead of the more expensive "Wizards") that foil Kramer's run for condo board president. In "The Heart Attack", Kramer explains how Bob had a botched hernia operation, so that now he has a high-pitched voice and spends his days in a wheelchair. He also had rabies at some point. Bob provided a bag of defective condoms to Kramer in "The Fix-Up", which George used with Elaine's friend, whom he briefly believed he had impregnated. Bob once stayed at Kramer's apartment as a guest for a year and a half. Larry Charles created Sacamano, naming him after a real-life friend. Bob also befriended Jerry when Jerry and Kramer trade apartments.
Lomez, an unseen friend of Kramer's. He is an Orthodox Jew, "old school," according to Kramer in "The Fatigues". In "The Betrayal", Kramer bangs on the door of a portable toilet yelling "Come on Lomez, we're going to miss the movie!" When Kramer starts the Peterman Reality Bus Tour in "The Muffin Tops", he notes Lomez's place of worship on the tour. Kramer purchases a hot tub from Lomez and speaks on the phone to him while taking a shower in "The Apology". In "The Package", Kramer tells Jerry that he traded his stereo to Lomez for some steaks. In "The Voice", Kramer's intern Darren tells Jerry and George that "Mr. Kramer's in a meeting with Mr. Lomez." And in "The Van Buren Boys", one of the Susan Ross Scholarship interviewees is credited, although not mentioned as, Lomez Junior. His only line is "You like that, don't you?" when George mentions that he has a 4.0 GPA. In "The Slicer", Kramer tells Elaine that Lomez blew his neighbour's circuit to stop an incessant alarm, prompting her to do the same. Later in the same episode, Kramer tells Elaine that, in blowing his neighbour's circuit, Lomez caused the automatic cat feeder to stop functioning, resulting in incessant meowing from the neighbour's cat. When Elaine asks Kramer what Lomez did about it, he replies that "He moved to a hotel and the cat eventually died".
Jay Riemenschneider, a friend of Kramer's. Kramer once mentioned that Jay "eats horse (meat) all the time" ("The Seven").
Corky Ramirez, a friend of Kramer's "up on 94th street" ("The Little Kicks"). A friend of Kramer's called "Ramirez" appears at a bar in "The Van Buren Boys".
Len Nicademo, a friend of Kramer. Kramer moved in with Len when Len "had the gout" ("The Stand In").
Specter, a friend of Kramer's. Was said to have a fat fetish and that he never dated a woman under 250 lbs. Specter was also said to become a minimalist in "The Tape".
Jerry's Sister, referenced in "The Chinese Restaurant".
George's Brother, referenced in "The Suicide" and "The Parking Space".
Elaine's sister, Gail, referenced in "The Airport", "The Stake Out" and "The Pick".
Simons, one of George's friends who gave him stock exchange advice in the episode "The Stock Tip".
Aunt Sylvia, Jerry refers to his Aunt Sylvia during a conversation with Elaine on her front stoop in the episode "The Soup".
Sharon Besser, a woman from Jerry's past who in 1973 played a part in either the "greatest moment" or "worst moment" of his life. Mentioned in "The Pony Remark".
Jerry "Pachyderm" Persheck, also known as "The Derm" is referenced by all four major characters in the episode The Stand-In. One evening Pachyderm exclaimed that he was going to approach a woman; however, before approaching her he grabbed two pieces of pizza that were much too hot with his bare hands. Pachyderm, determined to approach the woman, held the two burning pieces of pizza in his hands until he resorted to juggling them which ultimately resulted in him throwing the pizza in the air. According to Elaine, the whole place "went crazy" when one piece landed on Pachyderm's face and the other landed on the woman's face. At the end of the episode George's girlfriend leaves him for Pachyderm who has apparently resorted to repeating the pizza event as a way to pick up women.
Ed Roidlick, a Seinfeld family connection in the advertising industry that Morty and Helen Seinfeld want Jerry to contact (and give up comedy) when they learn he has bounced a check ("The Little Jerry").
Dr. Bison, Jackie Chiles' doctor, who is mentioned by Jackie Chiles in numerous episodes.
Suzy, Jackie Chiles' receptionist/secretary who usually sets up appointments with Dr. Bison, but seems to appear in the series finale with Jackie Chiles.
Harry Fleming, Morty Seinfeld's employer as mentioned while in a meeting with J Peterman as he refers to 5:15 as "all hours of the night."
Mr. Wilkinson, Simons' friend who invested millions into Sendrax ("The Stock Tip).
Paco, A cook at Monk's Café, known for leaving rubber bands in the soup ("The Strike").
Aunt Baby, George's aunt who died at age seven ("The Money").
Uncle Mo, George's paternal uncle who died a young man of internal problems ("The Money").
Hennie, George's maternal cousin, once removed ("The Money").
Patty Lawrence, Jerry's ex-girlfriend who assures him by phone that she had orgasms while they were dating ("The Mango").