Katherine Yih became politically involved through Science for the People while a graduate student in agricultural ecology in Ann Arbor in the late 1970s. She helped organize an active support group for the Toledo-based Farm Labor Organizing Committee (FLOC), promoting FLOC's consumer boycott of Campbell's and Libby's, integral to the farmworkers' ultimately successful struggle to be included in contract negotiations with farmers and these tomato-canning corporations.

She was a founding member of the New World Agriculture and Ecology Group (NWAEG), an international organization that analyzes the problems of contemporary agriculture and ecology in order to develop and implement alternatives, on the premise that the recurrent problems of the human condition – including hunger, poverty, disease, and war – result from power differences between classes.

Katherine was active in Central America solidarity work as well. In 1982 she was recruited by the Nicaraguan Center for Research and Documentation of the Atlantic Coast (CIDCA), where she spent five years (1982-1987) doing research in support of regional development, including on gender relations in the collectivization of agriculture, mostly in and around Bluefields.

After returning to the U.S. and moving to Boston, Katherine worked for Oxfam America (1988-1990) and International Physicians for the Prevention of Nuclear War (1990-1993) as a researcher, writer, editor, and, at Oxfam, shop steward. She made a career shift into public health in the mid-1990s, working as an immunization epidemiologist and program manager with the Massachusetts Department of Public Health (1996-2000), the Pan American Health Organization in Brazil (2000-2001), and the Department of Ambulatory Care and Prevention of Harvard Medical School and Harvard Pilgrim Health Care (2002-present).

Katherine has served on GRI's board during two eras, 1990-1996 and from 2002 to the present. She currently chairs the Board Development Committee.