Probably due more to his dress than his manners, the villains Jim Craddock was given the name Gentleman Ghost. Oh, and he is a ghost if the name didn't make that fact obvious. GG first appeared in 1947's Flash Comics #88.
Although never referred to as a Gentleman Ghost, the "Gentleman Jim Craddock," was addressed as such in his first onscreen appearance in the appropriately titled 1977 episode of the All New Super Friends, The Ghost. Ol Jimmy boy even turned Superman and Wonder Woman, along with members of the United Nations into super friendly ghosts.
It would be nearly another 30 years before Gentleman Ghost returned from beyond for his next appearance in Justice League Unlimited in 2006. In Ancient History, Ghostie put up a weak effort before being bottled and netted by GL and Hawkman.
In Batman: The Brave and the Bold, GG played a recurring role first facing off against the likes of the also dead Deadman.
In Trials of the Demon! an episode perhaps inspired by Gotham by Gaslight, Gentleman Ghost's back story was "fleshed" out. The tale was set in 19th century London during the days of Sherlock Holmes and the still living Craddock was revealed as the primary villain.
But Craddock best laid plans gang aft agleyed and viewers witnessed his transformation from man to phantom finally giving the somewhat silly villain gaining some street cred.