Major General Park Chung Hee, frustrated by the political turmoil that characterized the Second Republic of South Korea, spearheaded a military coup on May 16, 1961. This coup was orchestrated by the Korean military, which had become increasingly disillusioned with the rampant corruption and inefficiency of the civilian government. The Second Republic had been in place since 1960 after widespread protests led to the resignation of President Syngman Rhee. However, the new government struggled to address the economic challenges and political instability, prompting military leaders to take drastic action.

With the backing of several military units, Park and his forces swiftly took control of key sites in the capital, Seoul, including the government buildings and broadcasting stations. The coup was executed with precision, resulting in little resistance from the police or the public. Within hours, Park declared martial law, effectively suspending the constitution and shuttering the National Assembly. This action led to the arrest of numerous political figures and dissenters, consolidating power within the military.

Park Chung Hee's rule ushered in an era of significant changes within South Korea. He focused on economic development policies that would lay the groundwork for rapid industrialization, known as the 'Miracle on the Han River,' although his government was characterized by authoritarian control and suppression of political dissent.