King really did popularize it-- or mainstream it, I suppose-- but it's been around for a while. There was Night Stalker
in the early 70s, various Hammer films set in contemporary times, Creepy
in the 60s, EC in the 50s; all had stories of traditional horror in the (then) modern setting. I'm not especially familiar with Horror literature of those periods, but I'm sure there are examples there, too.