Marilyn Harris was born on June 4, 1931, in Oklahoma City, Oklahoma, the daughter of John P., an oil executive, and Dora (Veal) Harris. Harris was educated in her home state, attending Cottey College from 1945 to 1951, then transferring to the University of Oklahoma, where she received a bachelor of arts degree in 1953 and a master of arts degree in 1955.

Harris's first collection of short stories, King's Ex, was published by Doubleday in 1967. After that Harris proved a prolific author, publishing seventeen books, including novels, short stories, romance/ historical fiction and children's fiction in a twenty-year period from 1970 to 1989. These works included In the Midst of Earth (1969), The Peppersalt Land (1970), The Runaway's Diary (1971), Hatter Fox (1973), The Conjurers (1974), Bleeding Sorrow (1976), The Portent (1980), The Last Great Love (1981), Warrick (1985), Night Games (1987), and Lost and Found (1991).

Harris also wrote the widely known, sevennovel "Eden" series, a historical saga about the Eden family of...