The Gary Coleman Show was spun off from a TV-movie Coleman (Diff'rent Strokes) made for NBC earlier in 1982, "The Kid With the Broken Halo". For the cartoon, Coleman reprises his role as Andy LeBeau, sent back to Earth to foil the mischief-making Hornswoggle (not to be confused with the WWE wrestler of the same name, who came along nearly 25 years later).
Unfortunately, this Hanna-Barbera entry lasted just 1 season, and was ultimately replaced by Alvin & the Chipmunks in the post-Smurfs slot on the NBC schedule. Joseluisqld uploaded the open to YouTube. I should note that the voiceover by announcer Casey Kasem, who did all the bumpers for NBC in those days, was deleted from post-network prints.