Ruthie Cohen

The Monk’s Cafe cashier who appeared in a whopping 101 episodes, Ruthie Cohen’s most memorable moment was when George accused her of stealing a $20 bill he still had in his own wallet. The actress, who had the same name as her character, died of a heart attack in 2008 at age 78.

Jerry Stiller

From Festivus to his TV Guide obsession, Jerry Stiller’s Frank Costanza was such a huge presence that it’s hard to believe he was only in 24 episodes. Jerry Stiller passed away in his sleep in May of 2020 at the age of 92, following a career that lasted more than 60 years.

Barney Martin

While Frank and George Costanza shared some similar traits, Jerry Seinfeld and his father, Morty, seemed quite different, which occasionally led to conflict. Barney Martin played the role for 19 episodes, and died of a heart attack in 2005 at age 82.

Len Lesser

In a cast filled with countless memorable weirdos, Jerry's Uncle Leo is still one of the strangest, and the part remains the best known of prolific character actor Len Lesser’s career. Sadly, his career came to an end in 2012 at age 88, when he passed from cancer-related pneumonia.

Richard Herd

No one was more baffled or unsettled by George's unruly work behavior than his boss at Yankee Stadium, Mr. Matt Wilhelm, who was played by Richard Herd. He appeared in movies and TV until his death in May 2020, following cancer complications.

Ian Abercrombie

From cutting his Snickers bars with utensils to needing a specific kind of white sock, Ian Abercrombie’s Mr. Pitt gave Elaine her most challenging job of all. A familiar face in the UK and the US, Abercrombie passed away from kidney failure complications in January 2012 at 77 years old.

Sandy Baron

Played by comedy and Broadway legend Sandy Baron, Jack Klompus was Morty Seinfeld’s nemesis at Del Boca Vista. Sadly, the actor died in February 2001 at the age of 64, after battling emphysema for a number of years.

Warren Frost

Played by “Twin Peaks” alumni Warren Frost and Grace Zabriskie, Mr. and Mrs. Ross made no secret that they thought George was terrible for their daughter, Susan. Frost passed away in February 2017 at age 91, following one final appearance on “Twin Peaks: The Return.”

Daniel von Bargen

He may have only appeared on four episodes, but George’s deadpan, lackadaisical boss Mr. Kruger was a huge scene stealer. Tragically, actor Daniel von Bargen passed away in March 2015 at age 64, after a long battle with diabetes complications and mental illness.

Reni Santoni

Poppie, the owner of a well-known Italian pizzeria, caused a lot of damage in his four episodes, including not washing his hands before cooking and urinating on a couch. Actor Reni Santoni, best known for his work in “Dirty Harry,” passed away at 81 in August 2020 after a long illness.

Billye Ree Wallace

Wallace appeared in three episodes as Jerry’s Nana, with her most memorable appearance being the time Jerry decided to cash all of her birthday checks. In March 1999, Wallace passed away from respiratory failure and emphysema at the age of 73

Frances Bay

In one of Jerry Seinfeld’s pettiest moments, he attacked a little old lady, Mabel Choate, over a marble rye. Actress Frances Bay brought impeccable timing to the role, and she passed away at age 92 in 2011, following a long career.

Elmarie Wendel

The fourth season briefly saw Kramer moving to Los Angeles, where he met a former actress named Helena played by Elmarie Wendel. best known for her work on “Third Rock From the Sun,” Wendel passed away in July 2018 at age 89.

The Mandelbaums

The three generations of Izzy Mandelbaums (who all appear to be the same age) were memorably played by Lloyd Bridges, Gene Dynarski, and Earl Shuman. Sadly, all three have since passed away, as Bridges died in 1998, followed by Schuman in 2016, and Dynarski in 2020.

Sam Lloyd

In Elaine's extensive catalog of men who become obsessed with her, Sam Lloyd’s Ricky is one of the creepiest. Lloyd was best known for his work on “Scrubs,” and he was only 55 when he was diagnosed with a brain tumor and lung cancer, dying shortly after in 2020.