The National Assembly of the Republic of Korea (South Korea) voted in favor of allowing dual citizenship (156 in favor, 19 against, and 17 abstentions) in April 2010. Using South Korea as a case study, I make one methodological and one substantive argument regarding official acknowledgment of dual citizenship. First, de jure acknowledgment of dual citizenship will be likely to exhibit a path-dependent progression, from zero tolerance, to mere tolerance, and to official acknowledgment. Therefore, I argue that a study of dual citizenship needs to take into account various legislative changes that are indicative of increasing tolerance toward dual citizenship. Substantively I argue that introduction of de jure dual citizenship in South Korea indicates officialization of the strategy of flexible citizenship employed both by upper-class South Koreans and by the South Korean government. For upper-class South Koreans, dual citizenship has become a strategy to pass their class privilege on to their children while, for the South Korean government, dual citizenship has become a strategy to attract resource-rich overseas Koreans and global talent.