One major part of the show's running storyline is a falling-out between Kevin and Winnie, who becomes a background character for several months until she and Kevin reconcile. The primary reason for this part of the storyline was that actress Danica McKellar had a growth spurt, and she and star Fred Savage, already shorter than McKellar, didn't look right standing together. The characters reconciled after Savage began to catch up in height.
At the end of the episode of the finale, the voice of the narrator's kid at the end is Daniel Stern's son Henry - the producers wanted them to end the show talking to each other.
Actor Jason Hervey said that the scenes where he inched the car forward as Kevin tries to get in happened because his older brother did the same thing with him.
An actual narrator on-set was reading aloud the voiceover lines to make it easier for Fred Savage to react to the voiceover dialogue.
Bob Brush said the show got a lot of fan mail in the last season about how Kevin and Paul were not as close as they once were. He said this was intentional, as Kevin, now with a driver's license, could associate with whoever he wanted, and he and Paul changed as they got older. He said this is how most friendships realistically evolve.