The Sunshine Policy, a new type of engagement policy of South Korea towards North Korea, was set by the administration of the president Kim, Dae-joong in 1998 and lasted for a decade until the opposition party took over the ruling party seats. Since the policy was implemented, whenever North Korea has raised the level of security threat with its missiles or taken war-provoking postures, the Sunshine Policy has been brought to the discussion table domestically and internationally, and there always has been mixed opinion about the policy’s efficacy. This essay sets forth the views on why the Sunshine Policy should be regarded as a successful government policy, supporting them by using the ideas of strategic moves and commitment. From the strategic move point of view, the Sunshine Policy was a new initiative for direct conversation with North Korea (the North) and it achieved the first mover’s advantage in a strategic move by inducing the North to take a cooperative attitude toward South Korea (the South), consistently showing the South Korean government’s commitment on the promise of the ‘economy and politics separation principle’. When applying the commitment device concept, the Sunshine Policy could be considered a commitment device maker, as it created the joint industrial zone as a symbol of the inter-Korean cooperative economic development, and two Koreas had negotiated more than 40 different types of agreements during the decade in the period of the Sunshine policy. Hence, it could be said that the Sunshine Policy contributed to enhance the probability of sustaining the security on the Korean peninsula.