The voice of Mudsy was provided by Daws Butler and was identical to his voice work for Snagglepuss, down to the use of Snagglepuss's catchphrases, "even". (In turn, that voice was an impersonation of actor Bert Lahr.)
In the 1970s, comic books of The Funky Phantom were released by Western Publishing and Gold Key Comics. The comics were both original stories as well as adaptations of some of the TV episodes. The stories in the comics, however, took a different turn from the TV episodes.
While on the show, the "ghost" was always a villain in a mask (like Scooby-Doo), in some of the original comic stories, the villains would often turn out to be other ghosts from on or around the colonial era.
With the heavy production load at Hanna-Barbera Productions, this became their first series to have the animation done overseas (Austrailia).
Like many animated series created by Hanna-Barbera in the 1970s, the show contained a laugh track created by the studio, one of the first productions to do so. Syndicated versions on Cartoon Network and Boomerang have the track muted.