Schorer earned an MA at Harvard and his Ph.D. in English at the University of Wisconsin–Madison in 1936. During his academic career, he held positions at Dartmouth, Harvard, and the University of California, Berkeley, where he chaired the Department of English from 1960 to 1965. A leading critic of his time, he was best known for his work, Sinclair Lewis: An American Life. Schorer was also the author of many short stories, which appeared in magazines such as The New Yorker, Harpers, The Atlantic Monthly, and Esquire.
Among his honors were three Guggenheim Fellowships, a Fulbright professorship at the University of Pisa and a fellowship at the Center for Advanced Study in Behavioral Sciences at Stanford. He also was elected to the American Academy of Arts and Sciences, the most prestigious honor society for creative arts in the country.
Schorer was called as an expert witness during the 1957 obscenity trial over the Allen Ginsberg poem Howl, and testified in defense of the poem. This incident is dramatized in the film Howl (2010), in which Schorer is portrayed by Treat Williams.
In addition to his scholarly works, he also co-authored a series of science-fiction and horror stories with writer, publisher and childhood friend (both being natives of Sauk City, Wisconsin) August Derleth. These stories, originally published mainly in Weird Tales magazine during the 1920s and 1930s, were eventually anthologized in Colonel Markesan and Less Pleasant People (1966).
- "Mark Schorer author, biographer dead at 69," Wisconsin State Journal August 16, 1977. p. 21, col. 1
- "Author: Mark Schorer", LibraryThing website
- "Author Schorer, 69, Dies," Oakland Tribune, August 13, 1977 p. 42, col. 3
- Campbell, Jason (June 1, 2007). "To Save America". The Guardian. London.
- Stark, John O. (1977), ""Wisconsin Writers: Mark Schorer"", in Theobald, H. Rupert; Robbins, Patricia V. (eds.), State of Wisconsin Blue Book 1977, Madison, Wisconsin: Wisconsin Legislative Reference Bureau, p. 157
- "Schorer, Mark: 1908-1977 Novelist, Biographer, Scholar and Teacher". Wisconsin Historical Society. Retrieved May 10, 2019.
He began to publish stories in smaller magazines and work alongside his childhood friend, August Derleth, publishing articles in pulp magazines.
- "MARK SCHORER DIES; NOVELIST AND CRITIC". The New York Times. New York, New York. August 18, 1977. p. 24.