The United States sent its first envoy to Korea in 1883. The United States led the U.N. coalition that fought a war to defend the Republic of Korea (ROK) after the Democratic People’s Republic of Korea (DPRK) invaded it in 1950. The United States and the ROK signed a mutual defense treaty in 1953 and have worked closely together ever since to provide security in the region, address global challenges and advance mutual interests.

Here is a brief timeline of U.S.-ROK diplomatic history and cooperation since the mid-20th century.


Aerial view of mountain terrain at 38th parallel (© AP)
ROK troops at a mountain lookout post along the 38th parallel. (© AP)

Following Japan’s surrender at the end of World War II, the Korean Peninsula is divided at the 38th parallel into two occupation zones.


Douglas MacArthur sitting next to Syngman Rhee (© Charles Gorry/AP)
ROK President Syngman Rhee (right) and General Douglas MacArthur, supreme allied commander in Japan, at the inauguration of the new republic in August 1948 (© Charles Gorry/AP)

The parties do not realize their hopes for a unified Korea and instead establish two separate nations: the ROK in the south and the communist DPRK in the north.


Soldiers walking on an airfield (© Max Desfor/AP)
U.S. Marines regained control of Seoul’s Kimpo airfield in September 1950, three months after the DPRK invasion. (© Max Desfor/AP)

DPRK forces invade the ROK. Led by the United States, a 16-country U.N. coalition undertakes the ROK’s defense while the People’s Republic of China enters the war on the DPRK’s side.


3 men looking at a document (© George Sweers/AP)
ROK President Syngman Rhee (right), after signing the mutual defense treaty that he said would deter aggression and strengthen world security (© George Sweers/AP)

An armistice ends the fighting, but the parties do not sign a peace treaty. The United States and the ROK sign their mutual defense treaty.


Woman teaching other women (Peace Corps)
Peace Corps Volunteer Nancy Hamm conducts English workshops for teachers in the ROK. (Peace Corps)

President John F. Kennedy signs the Fulbright-Hays Act in 1961, and a bilateral U.S.-ROK Fulbright agreement follows a couple years later. (By 1972 the Korean-American Educational Commission is established.) To date, more than 32,000 U.S. and ROK citizens have participated in government-sponsored academic exchanges.

The Peace Corps begins sending volunteers to the ROK in 1966 to teach English and advise on health care, often in rural settings. By 1981, it will have sent more than 2,000.


Cars lining up in rows (© Bullit Marquez/AP)
KIA sedans and SUVs made in the ROK await transport to car plants and eventually to showrooms. (© Bullit Marquez/AP)

The U.S. market plays an important role in the ROK’s export-led development, a trend that began in the 1960s. By the 1980s, ROK exports shift from textiles to higher-value products, such as automobiles and integrated circuits. (By 2020, ROK companies will be major investors in the United States, with foreign direct investment (FDI) of $62 billion. For its part, the United States also becomes a robust investor in the ROK, with a 2020 FDI level of roughly $34 billion.)


Children learning in a classroom (USAID)
USAID invests in educational systems in 50 countries, providing 24 million young people educational access each year. (USAID)

Korea International Cooperation Agency (KOICA), the official aid agency of the ROK, is founded. KOICA currently partners with the U.S. Agency for International Development to advance education, health, economic security and other priorities around the world.


K-pop group BTS performing on stage (© Chris Pizzello/AP)
The ROK pop group BTS performs in 2019 in Inglewood, California. (© Chris Pizzello/AP)

The “Korean wave” begins its sweep through the United States, with K-pop artists, films and TV dramas and Korean cuisine captivating Americans. It is a phenomenon that continues today.


Donald Trump shaking hands with Moon Jae-in (© Andrew Harnik/AP)
President Donald Trump and ROK President Moon Jae-in at the Blue House in Seoul, ROK, November 7, 2017. (© Andrew Harnik/APP)

The first Korea-U.S. free trade agreement enters into force in 2012. Five years later, in 2017, President Donald Trump pays the first state visit to Seoul by a U.S. president in 25 years. In 2018, Trump and President Moon Jae-in sign a landmark, revamped free trade deal.


U.S. and South Korean forces participating in a military drill (© Ahn Young-joon/AP)
U.S. Army and ROK soldiers take positions during an exercise in January 2023. (© Ahn Young-joon/AP)

In 2021, President Biden and President Moon reaffirm joint commitment to ROK defense. The photo above shows ROK soldiers during an exercise. The two close allies continue to coordinate their response to the DPRK security threat and their efforts to achieve complete denuclearization of the Korean Peninsula.


President Biden and ROK President Yoon Suk Yeol walking down a red carpet (© Lee Jin-man/AP)
President Biden (right), and ROK President Yoon Suk Yeol (left), arrive for the state dinner at the National Museum of Korea in Seoul, ROK, May 21, 2022. (© Lee Jin-man/AP)

In 2022, President Biden pays his first visit to the ROK as U.S. head of state and is welcomed by President Yoon Suk Yeol. Biden affirms the U.S. extended deterrence commitment to the ROK, using the full range of U.S. defense capabilities.


White House place setting on a table (© Andrew Harnik/AP)
A place setting for a White House state dinner (© Andrew Harnik/AP)

President Biden and first lady Jill Biden plan a state dinner at the White House for ROK President Yoon and first lady Kim Keon Hee. The visit will commemorate the 70th anniversary of the U.S.-ROK alliance, which helps advance peace and prosperity for both countries, for the Indo-Pacific region and for the world.

Staff writer Lauren Monsen contributed to this story.
A version of this story was previously published April 12, 2019.