Hearst was born and raised on a farm just west of Cedar Falls, Iowa, in Black Hawk County. Having completed high school early, he started taking classes at Iowa State Teachers College (now the University of Northern Iowa) in Cedar Falls, sometimes riding horseback to campus from his family’s farm. During World War I, he volunteered for the U.S. Army and was called up in September 1918, but the war ended shortly and he was discharged by the end of the year.

On Memorial Day 1919, having returned to his family’s farm, Hearst was swimming with his friends in the Cedar River. He dove off the dock into the river, not realizing that, over the winter, it had become dangerously shallow. He hit the bottom with his head, fractured his spine, and was left substantially paralyzed for the rest of his life. That moment in his life, he said, was “my nineteenth year where footsteps end.” In the long process of recovering, he came up with ingenious work-around ways by which he could contribute to the operation of the farm, but, as his disability worsened, he increasingly turned to writing about plants, animals and people through the eyes of a Midwestern farmer.

Hearst’s early published work appeared in Wallace’s Farmer magazine. Over many years, his work was also published in The Nation, Des Moines Register, Chicago Sun-Times, Prairie Schooner, New York Herald Tribune, Ladies Home Journal, Saturday Evening Post, Harper’s, Saturday Review, Commonweal, North American Review, Poetry, Chicago Jewish Forum, Canadian Poetry Magazine, The Sparrow, Educational Leadership, The Instructor, America, American Friends Magazine, The Iowan, Kansas Magazine, Hawk and Whippoorwill, Compass Review, Poetry Dial, Discourse, The Humanist, Wormwood Review, Iowa English Workshop, Voyages to the Inland Sea, Virginia Quarterly Review, Heartland, Christian Science Monitor, and Growing Up in Iowa.

He was the author of ten volumes of poetry: Country Men (1937, 1938, 1943), The Sun at Noon (1943), Man and His Field (1951), A Limited View (1962), A Single Focus (1967), Dry Leaves (1975), Shaken by Leaf Fall (1976), Proved by Trial (1977), Snake in the Strawberries (1979), and Landmark and Other Poems (1979). Two other collections of his poetry were published posthumously: Selected Poems (1994) and The Complete Poetry of James Hearst (2001).

In addition, he produced two books of prose: My Shadow Below Me (1982, an autobiography) and Time Like a Furrow: Essays (1982).

The fall 1974 issue of the North American Review, an award-winning literary magazine published at UNI, was designated a "James Hearst Issue." It featured Hearst's poetry, a checklist of his published works, a narrative of his life, and others observations about the significance of his writings. Each year, the same magazine sponsors a competition called the James Hearst Poetry Prize.

Hearst was on the faculty at University of Northern Iowa from 1941 to 1975, during which time he held classes in the basement of his and his wife’s home at 304 West Seerley Boulevard in Cedar Falls. Following the deaths of James and Meryl Norton Hearst (in 1983 and 1987, respectively), their residence (as specified in James Hearst's will) became the property of the City of Cedar Falls "...to be used as a community arts center." After substantial expansion and redesign, the house began to function officially as the James and Meryl Hearst Center for the Arts in May 1989.