This paper analyzes how the Republic of Korea (Korea) halted the massive transmission of COVID-19 in just two months. The quarantine was achieved successfully without any need for a national lockdown because, simply, Korean citizens actively followed quarantine guidelines. During the 2015 Middle East Respiratory Syndrome (MERS) outbreak, the country recognized the importance of an early response in the form of a systematic approach and adopted the necessary procedures. Comparing the spread of COVID-19 among different countries, Korea demonstrated several distinct characteristics. First, the duration of the coronavirus crisis was relatively short, and Korea was able to flatten the coronavirus curve in a brief period. Second, Korea blocked expanded transmission of the virus without implementing a national lockdown. Third, the coronavirus pandemic did not lead to economic panic. Korea, which had developed an institutional response to infectious diseases prior to COVID-19, used a strategy of balancing quarantine measures with economic policies. The paper summarizes the specific measures Korea implemented to overcome COVID-19, and discusses the sustainability of the economy after overcoming the virus.