In this Forum the authors suggest that a growing intensity of contradictory public and private interests in education is a persistent force in education development stemming from the increasing centrality of education in contemporary society. Contrasting South Korea's effective policies ensuring equality of educational opportunity with its world-leading levels of family expenditures on private education services demonstrates this force. A brief comparison with the US also indicates that such a contradiction and symbiosis may likely to be more universal than is often assumed. This observation can be demonstrated in particular by a historical analysis of the consequences of dynamic conflict between public and private interests in the Republic of Korea (hereafter, South Korea), a centralised national system more equitable and effective than most. With its global leading-edge conflict between effective public education policies and dramatic runaway private actions by families to gain advantages for their children, this country illustrates where this dynamic might take education systems in the future, for better and worse. South Korea is then briefly contrasted with the United States, a large decentralised nation that struggles with educational equality and uneven effectiveness. Showing that a transforming synergy between public and private interests occurs in these contrasting education systems suggests a more universal pattern than is often acknowledged.