Seinfeld is known for its outrageous guest cameos and supporting characters, one of whom appeared in the show almost as much as the main four characters. The only character to appear in all 180 episodes of Seinfeld is none other than Jerry Seinfeld, with Elaine, Kramer, and George each missing from at least one episode. Out of Seinfeld’s nine seasons, only one recurring character came even remotely close to the main cast, while also appearing over twice as much as the next most-featured role.
Led by Jerry Seinfeld, Elaine Benes, George Costanza, and Cosmo Kramer, Seinfeld’s bizarre episodes were supported by various recurring figures that ultimately enhanced the show’s humor, with notable examples being Jerry's arch-nemesis Newman, Frank Costanza, Tim Whatley, J. Peterman, and David Puddy. Many of Seinfeld’s best recurring characters are connected to the main four by family, work, or their neighborhood, which fits into the series perfectly as various sources of daily minutiae. While Wayne Knight’s Newman is arguably Seinfeld’s best-remembered supporting character, his 41 episodes surprisingly only make him the sixth-most frequent appearing role of the series.
The only supporting character to top Newman’s numbers of appearances is Ruthie Cohen, the cashier at Jerry, Elaine, George, and Kramer’s favorite café, Monk’s. Played by actress Ruth Cohen, Ruthie’s Seinfeld debut was in the season 4 premiere, “The Trip,” which would be the first of her 101 episode appearances, according to IMDb. Beginning in season 4, Ruthie is seen in almost every single scene set at Monk’s Café, which is fairly often considering how much time the gang spends drinking coffee there. However, Ruthie is primarily only in the background of the scenes at Monk’s, as she only received lines opposite Seinfeld’s main cast on a few occasions.
While Ruthie technically appeared in 101 episodes, actress Ruth Cohen was only credited for the episodes in which she actually had dialogue, which were primarily in Seinfeld’s last few seasons. The three Seinfeld episodes in which Ruthie Cohen had lines opposite the main characters include season 7’s "The Gum," season 8’s "The Foundation," and season 9's "The Junk Mail." “The Gum” actually has a major storyline based around her, which references the fact that Ruthie is always in the background and around them at Monk's, but George has never said a word to her. After three seasons of playing the show’s most heavily-featured extra, Seinfeld's season 7 episode gave her a specific line of dialogue that said, “Your car is on fire. Merry Christmas!” Her delivery is said to George after he accuses her of shortchanging him, with the writers loving that she finally got a speaking line that also happened to be the source of George’s episodic misfortune.
Seinfeld remains the highlight of Ruth Cohen’s acting career, though the actress also had guest appearances on sitcoms like Malcolm and the Middle, Dharma & Greg, and The Golden Girls. While Ruthie didn’t have many lines on Larry David and Jerry Seinfeld’s sitcom, she was still brought back for Seinfeld’s season 9 ending alongside many of the series’ best-remembered supporting characters. Because of how much Seinfeld’s writers and creators enjoyed her presence as an extra from seasons 4-9, they decided to officially name her character after herself on the same episode that she finally received her first speaking line.