In the Seinfeld pilot, Kramer's character is called Kessler.
The pilot, “The Seinfeld Chronicles,” aired on July 5, 1989, before the series settled into its familiar names and format. Michael Richards’s eccentric neighbor is identified as Kessler, a temporary name used for the character who would soon become Kramer.
The change was connected to the character’s real-life inspiration, comedian Kenny Kramer, Larry David’s former neighbor. David initially hesitated to use Kenny’s name because he worried that the real Kramer might exploit the connection. Once permission was obtained, the character was renamed Kramer for the regular series.
The pilot’s naming history is unusually complicated. Early drafts reportedly used Hoffman for the neighbor, while George Costanza was once called Bennett. Later episodes even play with the inconsistency: “The Betrayal” refers to Kessler as the name on Kramer’s apartment buzzer. Thus, Kessler is the canonical answer for the character’s name in the original pilot, not a mistake caused by a viewer’s memory.