Nguyễn Cao Kỳ assumed the role of Prime Minister of South Vietnam in 1965, leading a distinct military junta that signified a pivotal change in the political landscape of the country during the Vietnam War. At the same time, General Nguyễn Văn Thiệu was designated as the chief of state, although his role was primarily symbolic. The backdrop for this reshuffling of leadership was the escalating American involvement in Vietnam and increasing instability caused by insurgent activities from the Viet Cong. The appointment was meant to bring about greater unity and resolve as the government grappled with civil unrest and the complexities of military strategy in response to North Vietnamese aggression.

Kỳ was known for his flamboyant personality and military background. Under his leadership, there was an expectation for a more aggressive approach against communist forces. His administration faced significant challenges, including intense guerrilla warfare and political division. The military junta's grip on power aimed to reassure both domestic and international audiences, especially the United States, that South Vietnam would adopt a strong stance against communism. This marked a significant increase in military control over political processes in South Vietnam, setting a precedent that would shape the governance of the country going forward.

As the Vietnam War intensified, Kỳ's government worked closely with U.S. military and government officials, further intertwining the fate of South Vietnam with American foreign policy. Despite this military rule, the junta faced significant opposition from various political factions within Vietnam, leading to ongoing instability and a lack of widespread public support for the government. The leadership dynamism during this time was reflective of broader trends in Southeast Asia, where military forces increasingly assumed pivotal roles in governance during periods of crisis and conflict.