Ka Hsaw Wa was born a member of the Karen, one of Burma's many ethnic minorities that has long been discriminated against by the ruling military regime in Burma. Ka Hsaw Wa grew up as the son of a doctor and enjoyed relative economic privilege in his youth. However, when he entered college he soon became active in political causes, and quickly developed into a strong student leader. The Burmese government attacked the students brutally in 1988, killing many. Ka Hsaw Wa was captured and tortured. He then left Burma, but re-entered the country in order to participate in a lengthy photographic campaign documenting environmental and indigenous destruction, as well as severe human rights abuses, including starvation, systematic rape, and the destruction of entire villages. Most of the problems he documented were connected to the construction and operation of a petroleum pipeline in the area of Yadana for the oil companies Unocal (U.S.-based) and Total S.A. (based in France).

In 1995 he co-founded Earth Rights International (ERI) with the express purpose of exposing and raising awareness of the inextricable links between human rights and environmentalism in Burma and beyond. Then with a group of US American Lawyers Ka Hsaw Wa lead a class-action lawsuit against UNOCAL. The class-action suite held UNOCAL accountable for the human rights and environmental abuses associated with building the pipeline, as well as the military "security" actions. UNOCAL settled the lawsuit for an undisclosed amount of money.

Ka Hsaw Wa continues his front-line activism, and was featured in the 2006 film, Total Denial.

Ka Hsaw Wa and EarthRights are also involved in the current struggle for democracy and human rights in Burma, wherein a number of protesters, including monks, have been killed, and hundreds of protesters arrested. They are working to bring an end to the current violence against the people. In response to the 2007 protests, Ka Hsaw Wa has said:

"As someone who experienced this regime's brutality in 1988, I am glad that this time around, the world is watching. But that is not enough. The international community, including multinational corporations, must act now to prevent further bloodshed in Burma. The people have suffered profoundly for too long — they have already sacrificed so much, and they will not stop."

Ka Hsaw Wa has been awarded the Goldman Environmental Prize, Reebok Human Rights Award, Whitley Fund for Nature/Sting and Trudie Styler Award for Human Rights and the Environment, and the Conde Nast Environmental Award for his work in defense of human rights and the environment.