Marty Krofft accepted guardianship of Jack Wild while the teenage boy was in America filming the show. Krofft had 2 teenage daughters, and said later that Wild "made my life Hell."
Paul Simon successfully sued Sid Krofft and Marty Krofft for plagiarizing his song, "The 59th Street Bridge Song (Feelin' Groovy)." As a result, Simon got a writing credit for the series theme song.
The Kroffts sued McDonalds for copyright infringement because Mayor McCheese and Big Mac bore a strong resemblance to H. R. Pufnstuf. They also noted similarities between the living trees and apple pie trees.
The H.R. Pufnstuf character was originally created for the HemisFair '68 world's fair in 1968. The Kroffts produced a show called Kaleidoscope for the Coca-Cola pavilion headlined by a dragon named Luther, who became the year's symbol of the fair. The Kroffts overhauled the design and changed his colors, with plans to name the show "Lutherland" until a friend suggested "Pufnstuf," which he derived from the recent hit song "Puff the Magic Dragon." Jim Nabors laid down vocal tracks for Luther, but his recording was unusable, so he was replaced by mimic Lennie Weinrib, who continued to use the same voice for Pufnstuf.
Only two actresses auditioned to play Witchiepoo. Penny Marshall was first, but they felt that she wasn't right for the part. Stage veteran Billie Hayes came in next, let out a maniacal cackle, and hopped up on a desk. She got the part on the spot.