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 bricoleurin 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. Harper has taught sociology at SUNY Potsdam, the University of South Florida, and Duquesne University, and as a guest professor at the University of Amsterdam and University of Bologna. He edited the academic journal Visual Studies during its first thirteen years and wrote five works of visual ethnography published by the University of Chicago Press. His Visual Sociology is a comprehensive treatment of the topic. Harper was co-founder of the International Visual Sociology Association with Leonard M. Henny and others; in 2013 he was elected its president. He has had many photographic exhibitions in the US and abroad.
Books
2014: I Simboli del fascismo nella Roma del XXI secolo, cronache di un' oblio. Douglas Harper, Francesco Mattioli. Aciraele-Roma: Bonnano.. In Press.
2012: Visual Sociology. Douglas Harper. London: Routledge.
1998: Mondi Da Vedere: Verso una sociologia piu visuale. Patrizia Faccioli and Douglas Harper, editors. Milan: FrancoAngeli.
1994: Cape Breton, 1952: The Photographic Vision of Timothy Asch. University of Southern California: Ethnographics Press; International Visual Sociology Association.
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.
Films
2013: The First Step to Recovery. 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.