Putney was born and raised in New York. She attended Syracuse University, earning degrees in English literature and Industrial design.[1] She served as the art editor of The New Internationalist magazine in London and worked as a designer in California[2] before settling in Baltimore, Maryland in 1980[2] to run her own freelance graphic design business.[1]

After purchasing her first computer for her business, Putney realized that it would make writing very easy. She began work on her first novel, a traditional Regency romance, which sold in one week. Signet liked the novel so much that it offered Putney a three-book contract immediately.[2] In 1987 that first novel, The Diabolical Baron, was published. Since then, she has published twenty-nine books (as of January 2007). Her books have been ranked on the national bestseller lists of the New York Times, USAToday, and Publishers Weekly. [1] The vast majority of her works have been historical romance, although she did write three contemporary romances. She has also begun writing fantasy romance and romantic fantasy as M.J. Putney.

According to IUP (Indiana University of Pennsylvania) Magazine, Mary Jo Putney wed John Rekus (IUP alumni 1990), a consulting engineer, on April 14, 2012 at the castle at Maryvale. They reside at their estate in Ruxton, Maryland along with their four cats.