John Gegenhuber is Resident in The Bris (Season 5 - Episode 5).
John Kapelos is Barry Prophet, the sniffing accountant in The Sniffing Accountant (Season 5 Episode 4).
John Lizzi is the other guy (the third tenor) in The Doll (Season 7 - Episode 16).
John Michael Higgins is Kurt, Elaine's boyfriend in The Little Jerry (Season 8 Episode 11).
John O’Hurley is Jacopo Peterman. He appears in 20 episodes. The first is The Understudy (Season 6 Episode 23).
John Paragon is Cedric in 3 episodes. First: The Soup Nazi (Season 7 Episode 6).
John Posey is Dr. Fein (Dr. Tongue) in The Heart Attack (Season 2 Episode 8).
John Randolph was the first Frank Costanza in the original version of The Handicap Spot (Season 4 Episode 22).
Jon Gries is Homeless Man and Rusty in The Beard Jerry (Season 6 Episode 15) and The Bookstore (Season 9 Episode 17).
Jon Lovitz is Gary Fogel, George's and Jerry's friend in The Scofflaw (Season 6 Episode 13).
Jon Manfrelotti is Guy in Police Lineup in The Beard (Season 6 Episode 16).
Joseph Malone is Michael, Robin Sandusky's husband in The Good Samaritan (Season 3 - Episode 19).
Joseph V. Perry is Newsstand Owner in The Nose Job (Season 3 Episode 9).
