An analyst and administrator in the field of international development since 1975, Quilligan served as policy advisor and writer for many international politicians & leaders, such as Pierre Trudeau, François Mitterrand, Edward Heath, Julius Nyerere, Lopez Portillo Olaf Palme, & others.

An analyst and administrator in the field of international development since 1975, Quilligan has served as policy advisor and writer for many international politicians and leaders, including Pierre Trudeau, François Mitterrand, Edward Heath, Julius Nyerere, Lopez Portillo, Olaf Palme, Willy Brandt, and Jimmy Carter. He has been an economic consultant for government agencies in 26 countries, including the United States. He has also served as an advisor for several United Nations programs and international development organizations. Quilligan’s articles have appeared in the International Herald Tribune, the Manchester Guardian, the Christian Science Monitor, the Washington Post, Newsweek, Der Spiegel, the Economist, World Press Review, Tikkun, and other books and publications. Quilligan has given over 50 radio, TV and print interviews, including BBC and CBC radio; national, syndicated and local programs in the US and Canada.