AbstractThis article examines the reasons for the growth and decline of the Korean Protestant Church during the following five periods: In the early period of settlement (1884–1909), growth originated from the emancipation motif, modern values, the Christian's moral life, the Revival experience, Bible study, and the prayer culture. The Korean church did not polarize evangelism and social action. During Japanese domination (1910–1945), growth came from the respect of the people toward the church. The church served the nation, consoled and healed the minds of the people, and gave brave witness of their faith in God. However, political persecution, economic devastation, socialist influences, and finally the coercion of the Shinto shrine worship to the church blocked church growth. During the recovery time (1945–1960), the social anomie after the nation's liberation and the Korean War ironically became a seedbed for church growth. However, the church improperly made her image pro‐government and pro‐America. During the time of industrialization and urbanization (1960–1995), Korean Protestantism achieved great growth and the highest percentage. Most of the Korean Protestant churches in cities, taking advantage of the mass rural–city migration, were actively involved in evangelism and church planting. University mission organizations and military missions were most active. Yet, they did not do well in terms of holistic evangelism. On the other hand, the National Council of Churches in Korea (NCCK), the Urban Rural Mission (URM,) the minjung churches and others carried out social mission work. After the time of urbanization (1995–2005), church membership began to decrease. The Protestant church‐planting policy in city areas became inappropriate. In addition, the church's political conservatism fell out of favour with the young generation.