With its nuclear provocations and missile launches, North Korea has been viewed as a major impediment to building a cooperative security order in East Asia. What is puzzling, however, is that it is North Korea that has sparked a range of regional initiatives from South Korean governments. What is the role of North Korea in South Korea's search for a new regional order in East Asia? Does the nature of inter-Korean relations affect the types of regionalism sought by South Korean governments? To address these questions, I examine the scope and priorities of the regional initiatives led by the four South Korean presidents in the past two decades. I argue that the nature of inter-Korean relations and the foreign policy orientation of South Korean leaders in power explain the different types of regionalism pursued by South Korean governments.