Yu-Jin has worked on countless cases of military violence and brutal crimes against women in military prostitution. She has protested and sought legal support for the victims and victims' families for compensations and apologies from the US military. Yu-Jin and National Campaign staff have held a protest in front of the US embassy in downtown Seoul every Friday for the past ten years. Yu-Jin supported the organizing of civilians who live nearby Kuni bombing range (50 miles south of Seoul) one mile away from a rural fishing village, Maehayngri. The bombing range has been used by the US military since 1951, during the height of the Korean War. Bombing takes place 250 days a year, Monday through Friday, from 9 am until as late as 11 pm. Due to the noise and vibration from the jets and explosions, villagers suffer from high rates of depression, suicide, and post-traumatic stress disorder. They are also exposed to military toxins from the bombs. Some residents of Maehyangri, including children, have been killed by stray bullets and bombs. In April 2004, it was announced that the US military will return the land to South Korean jurisdiction by August 2005. Yu-Jin headed a successful class action suit with the residents of Maehyangri, which resulted in the granting of compensations to Maehyangri residents by the South Korean government.

Thanks in part to the work of Yu-Jin and the National Campaign, crimes by US troops in South Korea have decreased by one-third. The Campaign played a crucial role in proposing and negotiating the revision of Status of Forces Agreement (SOFA) between the US and South Korea. The revision included accountability of both governments for investigation and clean-up of bases that the US military is planning to return. The US military is also required to report to South Korean authorities within 48 hours of any contamination or accidents within the US military bases. The revision gives South Korea the right to persecute and imprison some military personnel under the Korean court system for crimes, but which crimes will be handed over to South Korea is still determined by the US military. This year, for the first time, two crimes committed by US soldiers were investigated and tried in South Korean courts. This is an historic event for South Korea – one that could not have happened without Yu-Jin and the National Campaign raising the level of awareness over the last nine years.

Yu-Jin publishes articles in prestigious, politically-progressive journals. Her written work is an important contribution to Women's Studies within South Korea and also to transnational feminist studies. Yu-Jin's work has inspired an activist independent filmmaker in Japan to make a film about Maehyangri. This film will soon be available with Japanese and English subtitles. Her work has also inspired women activists of the East Asia-US-Puerto Rico Women's Network Against Militarism to continue developing transnational solidarity among women. During the past two years, Yu-Jin worked for a governmental organization, the Korea Human Rights Commission.

According to Yu-Jin, the fact that such a governmental organization could exist in South Korea is significant. This is something no one could have imagined even ten years ago.

Currently, Yu-Jin is enrolled in graduate courses in peace and human rights at Osaka University. She intends to complete her master degrees in Peace Studies within the next few years.

Yu-Jin Jeong's persistent and powerful work has contributed to the protection of the rights of marginalized people, especially women, in Korea. Her work has raised the awareness of the negative impact of US militarism to a national level, and has helped people who were once powerless and oppressed to begin empowering and organizing themselves.

Yu-Jin's work is related to US militarism in South Korea: sexual violence against women, military prostitution, ecological and human devastation caused by military training and bombing practice, car accidents, violent fights with civilians, and petty crimes such as burglary and theft. Yu-Jin's primary goal is to protect and promote the rights of civilians, especially women and children, whose lives are further exploited, impoverished, and marginalized by militarism. She has worked on these issues with the National Campaign for Eradication of Crimes by US Troops.
Yu-Jin's work is unique in that it makes connections between imperialism, militarism, sexism, and classism that are specific to South Korea. The male-dominant, anti-imperialist nationalist movement in South Korea disregards the human rights of women and children. Because of Korea's patriarchal values, the women in military prostitution are easily dismissed and regarded as "dirty, lowly women" even by the politically progressive activists. Yu-Jin's method is participatory-she listens and supports the work of other organizations that are negatively impacted by militarism. Her method also involves empowering people by giving visibility and voice to those who are victims and survivors of military violence. Yu-Jin's activities are rooted in her understanding of solidarity-for her it represents "one's ability to feel the suffering of others who are different from you," nation/race/class/gender-wise.
Yu-Jin's work has influenced and inspired younger generations of feminist activists throughout South Korea. These younger women are promoting and carrying out public peace education, peace performances, and other nonviolent, creative actions in order to promote a culture of peace. The younger activists influenced by Yu-Jin are now leading the conscientious objector movement in South Korea.

South Korea's national security law has been used during three decades of US-backed military dictatorships to oppress political dissent. People who opposed the presence of the US military in South Korea were imprisoned as Communists in the name of national security even through the 1990s.

National Campaign for Eradication of Crimes by US Troops
Safe Korea
East Asia–US–Puerto Rico Women's Network Against Militarism