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The Two Koreas and the Vietnam War

By Daniel Oh

The Vietnam War was one of the most influential events during the 1960s, shaping how each Korea would view each other, as well as the United States.

Table of Contents


The idea that the Cold War was a conflict primarily fought without traditional military means can quickly be dismissed when considering the costs of the Korean and Vietnam Wars. For the United States, these two conflicts resulted in the heavy investment of its blood and treasure as it attempted to counter the perceived Communist threat. Scholars from numerous fields have covered these two wars extensively through the political, diplomatic, and military lenses. Aside from Vietnam itself, no other country was as affected by the Vietnam War as the U.S. Considered America’s longest war until recent times, the deep societal impacts of the conflict continue to shape decisions made by the U.S. government even today. Understandably, Western scholarship has been U.S-centric, though in recent years, viewing the event from an International History lens has continued to gain momentum.

It is a safe assumption that when asking the general public which country provided the second most foreign troops to the Vietnam War after the U.S., few would be able to provide the correct answer, the Republic of Korea (South Korea). In fact, an argument can be made that South Korea was affected as much, if not more, by the outcome of the Vietnam War as the U.S. Yet, the scholarship on South Korean involvement in the Vietnam War is not as prolific as one would expect given the importance of the event. When examining the country’s involvement in the war, the first, and perhaps the most critical question that should be addressed is why would South Korea choose to become so heavily engaged in a foreign conflict by 1965? As a matter of perspective, the country was only twelve years removed from the signing of an armistice that temporarily paused the war with its northern neighbor. South Korea was also only four years removed from a military coup that resulted in then Major General Park Chung Hee seizing power. Domestic politics were far from stable and the economy severely weakened. In fact, when compared to the Democratic People’s Republic of Korea (North Korea), the country was clearly lagging. It is in these conditions that South Korean troops became some of the first to enter South Vietnam in 1964 and among the last to depart nearly ten years later. During most of this period, the country maintained a force close to 50,000 in number while paying the price of nearly 16,000 casualties.

The strongest bond that tied South Korea and South Vietnam together was the United States. North Korea, on the other hand, had the potential of creating even deeper ties based on a common Communist ideology and the inextricable link that both countries had to the People’s Republic of China. If scholarship on South Korea’s participation in the Vietnam War is considered limited, works addressing the North’s involvement are downright scarce. Perhaps due to the limited amount of archival evidence available, the picture of North Korea’s role is still unclear which leads to the first critical question that should be answered, what was the extent of the country’s involvement? The available evidence suggests that North Korea had a small role, especially in comparison to the South, which leads to the question of why that was the case. A potential answer to this second question can be found not in Vietnam but rather with events back on the Korean peninsula itself. The armistice signed in 1953 between the North and the South may have halted conventional hostilities, but did not cease all military operations on the peninsula.

South Korea and the Vietnam War

To fully understand South Korea’s decision to commit its troops to Vietnam, one must first comprehend the political situation that its government was facing in the 1960s. South Korea had undergone a student-led revolution in 1960 resulting in the ouster of President Syngman Rhee, the country’s leader since 1948. Rhee’s administration had become increasingly autocratic in nature with clear ties to corruption, the most recent example being the 1960 presidential election that kept him in power. Adding to these difficulties was the poor state of the South Korean economy, which still relied heavily on American aid for survival. The democratically elected government under the leadership of Prime Minister Chang Myon succeeded Rhee’s regime in October 1960 but was in power less than year before a military coup led by Park Chung Hee occurred in May 1961. Though known to have good intentions, the Prime Minister was unable to quickly or decisively address the political and economic weaknesses of the country which led Park, with a close group of officers, to execute a Coup d'état. Pressured by the U.S. to allow free elections, Park was elected President in 1963, but only by a narrow margin. President Park faced the same challenges as his predecessors, the need to maintain power while addressing the country’s dire economic situation.

Adding to President Park’s domestic challenges were the international ones from the U.S. While the 1940s and 1950s had been the decades of free-flowing U.S. economic and military aid, in the 1960s the U.S. made efforts to drastically cut such programs. Calls for global reductions to economic and military aid packages became especially loud with the John F. Kennedy administration. One clear target was the Military Assistance Program which the South Koreans had greatly benefited from in the previous decades. Some estimates have the U.S. military assistance program as the source of 80% of South Korea’s yearly defense budget during the 1950s. Adding to the uncertain future of the aid programs was the continual planning for American troop reductions on the Korean peninsula. With an increasing focus on Southeast Asia, the Lyndon B. Johnson administration not only supported further cuts to South Korean economic and military aid, but also announced plans for actual troop reductions. The combination of political uncertainty, economic stagnation, and the diminishing American support presented immense challenges for President Park. Despite these clear obstacles, South Korea chose to make a significant contribution to the war effort in Vietnam and once it did, thousands of troops arrived in Southeast Asia within a short amount of time.

South Korean Troop Deployments to Vietnam

Coalition building can be one of the most difficult aspects of waging war. Normally, it is the burden of the state with the most interest in a war to recruit support and build a coalition against a perceived common threat. For the Vietnam War, aside from South Vietnam, the U.S. was the greatest stakeholder, though its level of resolve was still uncertain during the early 1960s. By 1964, the American commitment to South Vietnam solidified and the LBJ administration initiated a full court press of its “More Flags” program, an attempt to incite wide-ranging international participation in the conflict. The U.S. made it clear that it would support allied commitments by covering most, if not all, of the associated costs. With the introduction of U.S. combat troops in 1965, the need for “More Flags” increased exponentially.

In the case of South Korea, it is of interest to note that the Koreans had been offering troops for Vietnam since 1954, prior to any American requests. President Rhee made the first unsolicited offer in 1954, though it was quickly refused by the Eisenhower administration. During his first state visit to the U.S. in November 1961, President Park also unexpectedly offered his troops to President Kennedy in support of American efforts to rollback communism. President Kennedy also refused and stated that it was not the right time. President Park again made an offer to commit two combat divisions to President Johnson in 1964 and was again initially refused, though the U.S. did accept the deployment of non-combat units to Vietnam. By 1965, conditions had changed both politically and militarily. The Johnson administration was desperate for allied commitments of combat troops and South Korea was able to quickly fulfill the need.

The first troops sent to Vietnam fulfilled non-combat missions. South Korea’s deployments started with Tae Kwon Do instructors and a Mobile Ambulatory Surgery Hospital (MASH) in 1964. Its first major commitment came in the form of a 2,128 strong element known as the Dove Unit, which arrived in 1965. This element, composed primarily of construction, engineer, and medical units, focused on reconstruction efforts throughout the country. These troops operated under strict rules of engagement that prevented them from firing unless fired upon and chasing enemy forces outside its defined territory. Though it appeared that funding for these troops came from the South Korean government, it was actually the U.S. that covered the expenses, though not by direct means. The first major deployment of combat troops occurred later in 1965 with the arrival of the Capital Division (Tiger) supported by a marine brigade for a force totaling 18,904. The 9th Division (White Horse) with an additional regimental combat team and support elements arrived in 1966 at a strength of 23,865. When deciding upon which combat units to send to Vietnam, South Korea did not hesitate to send its best, as evidenced by the deployment of the Capital Division, the unit designated to protect Seoul.

The South Korean forces assumed responsibility of coastal areas from the Binh Dinh Province down to the Ninh Thuan Province. Though important for logistical considerations, the South Korean areas of responsibility were not heavy combat zones. The U.S. sought to place the Capital and 9th Divisions under American military operational control but the Korean government denied the request, citing concerns that its troops would be regarded as mercenaries. Internally, the refusal ensured that Korean troops were excluded from operating in high risk areas in Vietnam. The Commander of the Korean Forces in Vietnam, Chae Myong Sin, further argued that since the war was being waged on a political front, rather than a military one, the mission to rehabilitate damaged areas was just as important as engaging in combat operations. An agreement was reached that allowed Korean forces to operate independently under the command of a Korean officer, though he would be subject to the policy guidance given by the Free World Military Assistance Policy Council.

The South Korean forces received generally favorable evaluations from the American military. From a tactical standpoint, Korean units proved to be quite proficient and effectively secured their areas of responsibilities against Viet Cong forces. The Korean Civic Action teams also experienced a fair amount of success through its medical and reconstruction missions. Korean efforts, however, were not without controversy. Criticisms against the military’s ability to fully support the local governments along with its inability to sufficiently coordinate operations between sectors were clearly noted. The strongest critique, however, lies with the alleged heavy-handedness that the Korean troops used against the local population, especially during the early years of its deployment. It was perhaps the key reason why the military never fully received the support and cooperation from the Vietnamese.

Why Did South Korea Get Involved in Vietnam?

When considering why South Korea decided to make such a large contribution to Vietnam, two prevalent arguments exist. The first answer focuses on the political benefits of supporting U.S. efforts in Southeast Asia. President Park likely understood that the American commitment to South Korea would vary over time. With increasing indications that the U.S. wanted to reduce both aid and its military presence, South Korea found itself in a situation where its greatest guarantor of security was becoming less committed, while the North Korean threat was getting greater. Adding to these conditions was the fact that the 1954 U.S.-South Korean Mutual Defense Treaty did not have a clause that initiated an automatic response by the U.S. in the event of hostilities. President Park needed a way to ensure American commitment to South Korean security and the Vietnam War became the means to that end. At a time where no other country was enthusiastically responding to American calls for support in Vietnam, South Korea sought to ensure its own security by addressing the U.S. government’s greatest need at the time.

An alternate argument focuses on the economic benefits that resulted from South Korea’s involvement in Vietnam. With his two predecessors forcibly removed largely due to their inability to address the country’s economic situation, President Park likely understood the absolute necessity of improving the economy. Since its inception, South Korea had been relying on U.S. aid to keep its economy afloat, aid that was likely going to be reduced on a yearly basis. President Park’s revitalization plan was ambitious and not necessarily in line with the American economic experts in country. More importantly, it required an immense amount of capital to execute. It is no coincidence that the two events that are credited as being the twin engines to South Korean economic growth were both highly controversial and occurred in 1965, the normalization of relations with Japan and the deployment of combat troops to Vietnam.

When examining the effects of South Korea’s deployment to Vietnam, plenty of evidence exists to support both lines of argument. From the security standpoint, South Korea was successful in preventing both a reduction of U.S. forces and military aid during the 1960s. With a keen understanding of what the U.S. needed, the South Korean government proved to be unforgiving negotiators and extracted significant concessions. With its own security in mind, the Korean government successfully convinced the U.S. to suspend planned cuts to military assistance while gaining additional funding for the modernization of multiple Korean combat divisions. From 1965 to 1971, South Korea received 170 aircraft, 190 missiles, 25 naval ships, and 630 combat vehicles while over 300,000 troops gained combat experience. The U.S. also covered all the expenses in Vietnam at an estimated $927M to maintain Korean forces in the country from 1965-1970 and an additional $1B for personnel pay and allowances from 1965-1973. Though the situation would change drastically under the Nixon administration as the Vietnam War stumbled to a close in the 1970s, South Korea successfully kept the U.S. fully committed to its defense for another decade with its involvement in Southeast Asia.

The economic benefits of the troop deployment are even more staggering. Certain estimates state that the total worth of South Korean earnings from 1965 to 1972 for its Vietnam commitment was over $1B. It is through this capital that President Park was able to finance his five year developmental plan in support of his export led industrialization policy. South Korean exports increased ten times over from 1964 to 1973 while the government secured an estimated $2.7B in foreign loans by 1971 with U.S. assistance. The U.S. also allowed more Korean companies to compete for American procurements in support of the war. The Vietnam War provided similar opportunities to Korean companies as the Korean War did for Japanese ones. South Korea’s GDP tripled during this time while its war revenues made up nearly 40% of its exchange earnings. With such astounding figures, unlike the reception that American veterans received at home, there was a level of recognition by the Korean public of the sacrifice made by its Vietnam War veterans to support the revitalization of their country.

North Korea and the Vietnam War

The idea that North Korea supported the North Vietnamese against the U.S is one that was generally accepted for decades. Little is still known, however, of the extent of North Korea’s involvement, though more details have emerged in recent years. It was only in the year 2000 that both Vietnam and North Korea acknowledged the participation of North Korean pilots in combat missions against American aircraft. Though the exact numbers are unknown, one Vietnamese newspaper article stated that up to eighty-seven North Korean pilots had served in the war. Other archival documents suggest that North Korea provided a limited amount of non-military aid to North Vietnam and that it had sent personnel to observe the South Korean military operating in South Vietnam. These examples support one of two notions. The first is that much work still remains in clearly understanding the extent of North Korean participation in the Vietnam War. The second notion is that this lack of understanding may be because the country simply did not have a significant role in the conflict.

Coinciding with the heavy South Korean troop deployment to South Vietnam was an increase in belligerent operations by North Korean forces on the Korean Peninsula. The period between 1967 and 1969 is often characterized as the “Second Korean War.” These North Korean provocations were primarily irregular in nature as small scale attacks on both South Korean and American troops increased exponentially on a yearly basis. 1968 turned out to be the bloodiest year for the allies since 1953. 1968 was also the year that North Korea executed two critical operations that would cause President Park to reassess the security situation on the peninsula and his level of commitment to Vietnam. On January 17, 1968, thirty-one North Korean soldiers crossed into South Korea with the mission to assassinate President Park. Though only one soldier survived, the North Korean element was able to reach the outskirts of the Blue House compound on January 21st. The raid resulted in the death of sixty-eight South Koreans and three Americans. Three days later on January 23rd, the North Korean navy seized the USS Pueblo, an American spy ship, which would lead to eleven months of captivity for its crew.


The Tet Offensive commenced on January 31, 1968, eight days after North Korea seized the U.S.S. Pueblo. Whether the North Korean provocations were planned in concert with North Vietnamese operations is a matter open to debate. What is less debatable is the idea that Korean involvement in Vietnam had significant ramifications on both countries, both in Southeast Asia and on the Korean Peninsula. For the South Koreans, the Vietnam War proved to be a source of security and economic benefits early on in its involvement. As the war progressed, it faced many difficulties similar to the U.S. as both countries tried to figure out the best way to extricate their troops from the conflict. The worsening security situation on the peninsula lessened support for the Vietnam deployment but bringing home its troops was a decision that South Korea could not unilaterally make. For North Korea, though involvement in Southeast Asia appears limited, the Vietnam War likely shaped its decisions on the peninsula as it saw the attention of its two prime adversaries divided between two theaters for the first time since the country’s division. Whether examining the political, diplomatic, economic, or societal impacts of the Vietnam War on both countries, more questions certainly remain than answers. The war was arguably one of the most influential events during the 1960s as it strongly shaped how each Korea would view each other, as well as the United States, into the 1970s and beyond.


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