Holsti worked at Stanford University as an instructor in the Department of Political Science (1962-1965), the research coordinator and associate director of Studies in International Conflict and Integration (1962-1967) and assistant professor in the Department of Political Science, (1965-1967). He moved to the University of British Columbia in 1967, working as assistant professor in the Department of Political Science (1967-1971) before becoming a professor (1971-1974).
Holsti was at the University of California, Davis, as a professor in the Department of Political Science (1978-1979) before joining the faculty of Duke University as George V. Allen Professor in the Department of Political Science (1974-1998). He became a professor emeritus in 1998.