The "King Smurf" scarecrow seems to only reappear once or so after the events of this episode, namely in Season 7's "A Long Tale for Grandpa". Unfortunately, it's mis-colored and eaten whole by Rera Aphid in the same scene.
"King Smurf" is the first episode not to feature Gargamel and Azrael.
Based on the 1964 comic book story titled "Le Schtroumpfissime." It is the longest of the serialized Smurf stories that appeared in Spirou, spanning 37 issues. One major plot difference between that and the cartoon version is that, in the original, an unnamed Smurf becomes king and Brainy goes from being that Smurf's election opponent to King Smurf's loyal follower to a rebel who gets imprisoned in King Smurf's castle until its destruction, when Papa Smurf returns. Also, Smurfette does not appear in the original version.
"The Smurfs and the Howlibird" is based on the 1966 serialized comic story "Les Schtroumpfs et le Cracoucass" published in Spirou and published in an album in 1969 under the same name.
Jokey nearly "breaks the fourth wall" when he ponders on the situation that his being put into prison for pulling a prank on King Smurf was not a joke.