After graduation, Harper wrote a book, Good Company, about railroad tramps.
Harper made extensive use of photo elicitation interviews in his 1987 book, Working Knowledge, a sociological treatment of the rural bricoleur in America. His 2001 publication, Changing Works, applied the same method to the historical reconstruction of cultural memory.
Harper later co-authored books on post-colonial culture in Hong Kong, Italian food culture, and the semiotics of Italian fascism, in which he researched images as method of cross-cultural communication. In 2014, he studied the sociology of public space in the Italian piazza and in the de-industrialized regions of the American Rust Belt.
He has had many photographic exhibitions in the US and abroad.
2014: I Simboli del fascismo nella Roma del XXI secolo, cronache di un' oblio. Douglas Harper, Francesco Mattioli. Aciraele-Roma: Bonnano. ("The symbols of fascism: Reports of an oblivion"). In Press.[when?]
2012: Visual Sociology. Douglas Harper. London: Routledge.
2009: Hong Kong: Migrant Lives, Landscapes, and Journeys. Caroline Knowles and Douglas Harper. Chicago: University of Chicago Press.
2006: Good Company: A Tramp Life. Boulder: Paradigm. Douglas Harper. (Revised and expanded third edition).
2003: The Cultural Study of Work. Douglas Harper and Helen Lawson, editors. Boulder: Rowman Littlefield. 2004 Outstanding Title, designation by the American Library Association.
2001: Changing Works: Visions of a Lost Agriculture. Douglas Harper. University of Chicago Press. Scholarly Achievement Award, North Central Sociological Association and Collier Award, Society for Visual Anthropology.
1998: Mondi Da Vedere: Verso una sociologia piu visuale. Patrizia Faccioli and Douglas Harper, editors. Milan: FrancoAngeli.
1993: Eyes Across the Water, vol. II: Essays on Visual Sociology and Anthropology. Robert Boonzajer Flaes and Douglas Harper, editors. Amsterdam: Het Spinhuis Press.
1987: Working Knowledge: Skill and Community in a Small Shop. Douglas Harper. University of Chicago Press. Paperback edition, University of California Press, 1992.
1982: Good Company. Douglas Harper. University of Chicago Press. Second edition translations: Good Company: Un sociologo tra I vagabondi. Milan: FrancoAngeli, 1999 in Italian; Les Vagabonds du Nord-Ouest Américain. Paris: L'Harmattan, 1998 in French.
2013: The First Step to Recovery. (a 60-minute documentary film, in process.) Douglas Harper and Margaret Patterson, co-directors.
1983: Ernie's Sawmill. Douglas Harper and Stephen Papson, co-directors. A 16 mm, 20-minute ethnographic film.