Karate Kid had originated as a member of the Legion of Super-Heroes, a large group of super-powered teens from the future. Why the character was given his own title in 1976, one can only guess; after all, the kung fu movie craze had been sated for a while by then, and the replacement mania for ninjas wouldn't come around for a few years yet.
Still, for whatever reason, it was posited that the character - who had no real superpowers himself, only advanced martial arts abilities - grew restless with his role among his more obviously gifted teammates, and decidedly to live on 20th-century Earth for a while. Here he got into the usual scrapes with super-villains and petty crooks, but it never did quite come together as a series.
Although the first issue of the title was written by future DC Editor-in-Chief Paul Levitz, the scripting and art on the series never rose above a workmanlike level, and after fifteen issues it was decided to just finally put it to rest. Certain plot threads were tied up in Kamandi #58 and Brave and the Bold #199.