Featuring quirky horse-riding dance moves and an infectious electronic beat, an unlikely music video and its leading man made history in 2012. In December of that year, "Gangnam Style" reached one billion hits on YouTube--the most views ever. Seemingly overnight, the South Korean pop star behind the hit--Psy (Park Jae-sang)--became a household name.
But Psy is just part of the story. Other South Korean pop sensations such as Girls' Generation,...