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.
1945

Following Japan’s surrender at the end of World War II, the Korean Peninsula is divided at the 38th parallel into two occupation zones.
1948

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.
1950

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.
1953

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.
1960s

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.
1980s

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.)
1991

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.
2000s

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.
2012–2018

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.
2021

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.
2022

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.
2023

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.