The Third Republic was presented as a return to civilian government under the National Assembly but in practice was a dictatorship under Park, Supreme Council members, and the Democratic Republican Party.

The Supreme Council established a military junta headed by General Chang Do-yong and the May 16 coup's supporters in the Republic of Korea Army, hoping to kickstart South Korea's economic development that had been ignored for twelve years under the First Republic, and remove so-called "liberation aristocrats"—the ruling class of conservative politicians involved in the Korean independence movement.

The Supreme Council suspended the National Assembly, reinforced South Korea's anti-communist position, and undertook a number of economy-oriented reforms to help industrialize and develop the country, including the first Five-Year Plan.

The Supreme Council's military government was met with instant disapproval from South Korea's main ally, the United States, and Park's early attempts to appease the Americans were disregarded.

[1] The Third Republic was presented as a return to liberal democratic civilian government under the National Assembly, and a new powerful presidential system with the Prime Minister as the second-highest executive position under the President.

However, in practice, the Third Republic was a continuation of the military dictatorship under Park and his government was predominantly composed of former members of the Supreme Council, which often exercised significant autocratic powers.

The South Korean economy grew rapidly during the Third Republic and the government continued to economic development priorities set by the Supreme Council.

The Third Republic saw the first major construction of infrastructure in southern Korea since the Japanese colonial era, with many new roads, railways, and airports being built across the country.

The Third Republic continued the program with the government of West Germany to recruit South Korean nurses and miners as Gastarbeiter, which began in the final months of the Supreme Council.

The Koreans in Germany were able to wire large sums of money to South Korea because their wages, much higher than available back home, greatly exceeded their subsidized living costs.

][citation needed] In 1970, the Saemaul Undong (New Community Movement) was introduced that set out to modernize the countryside and their economies, in response to the growing wealth disparity with the richer urban areas.

Reportedly, Park could not stand the sight of thatched roofs on farmers' homes, which for him was a sign of South Korea's backwardness, and their replacement reflected a personal obsession rather than a practical necessity.

[4] Japan agreed to provide a large amount of compensation, grants, and loans to South Korea, and the two countries began economic and political cooperation.

During the 1960s, South Korea formed relations with Belgium, Greece, the Netherlands, Portugal, Iceland, Switzerland, Luxembourg, Austria, the Vatican City, and Malta.