Ken Hillís fascination with the Peace Corps began in 1965 when he served as a volunteer in Turkey with the economic development of small villages. His most recent, and final, assignment was acting chief of staff of Peace Corps. During the transition of administrations, he was, effectively, the chief operating officer of the $265 million Peace Corps program of over 7000 volunteers in 73 countries. Between 1994 and 1998 he directed Peace Corps country programs in the Russian Far East, Bulgaria and Macedonia and from 1999 through 2000 he was chief of operations for all Peace Corps programs in Europe and Asia.
Between tours with the Peace Corps, Ken held management positions with the ACTION Agency (federal volunteer programs), the Energy Department and the Office of Management and Budget. In 1975 he was appointed regional director for the Mid-Atlantic Region of ACTION and later as deputy associate director of domestic operations for ACTION was responsible for operational management of ACTION's ten federal regional offices and the recruitment of Peace Corps and VISTA volunteers. He worked to support the commercialization of alternative energy sources at the Department of Energy in 1979 and was a member of the Debt Collection project team at the Office of Management and Budget in1980.