Andrews was born Marietta Fauntleroy Minnigerode in Richmond, Virginia. Her sister Lucy Minnigerode was head of the United States Public Health Service Nursing Corps. She was of German descent, being the granddaughter of Charles Minnigerode, a revolutionary who fled to the United States in the 1830s due to his radical sentiments. She studied at the Corcoran School of Art in Washington, D.C. under Eliphalet Frazer Andrews, whom she would marry in 1895. She also studied in New York City with William Merritt Chase, with Luigi Chialiva of Paris, and Ernest Lieberman in Munich. Beginning in 1890 she served as an assistant instructor at the Corcoran School. She visited Italy in 1892, and in 1896 became a founder member of the Washington Water Color Club.
She produced designs for the stained glass windows of St. Paul's Church in Steubenville, Ohio. Her work may also be found at the University of Virginia, the George Washington University, and the American Society for Psychical Research. She published several books which she illustrated herself, including My Studio Window (1928); Scraps of Paper (1929); and George Washington's Country (1930); and also created silhouettes. Andrews died at her home, Vaucluse, in Alexandria, Virginia.
A sketchbook by Andrews, along with a collection of her drawings, was long held in the collection of the Corcoran Gallery of Art; at that institution's demise, all of these were transferred to the art museum at American University. A collection of her papers may be found at Virginia Commonwealth University.
- Andrew J. Cosentino (17 November 1983). The Capital Image: Painters in Washington, 1800–1915. Smithsonian. ISBN 978-0-87474-338-8.
- "Tradition – Christmas Trees, the Confederacy, and Colonial Williamsburg : The Colonial Williamsburg Official History Site". Retrieved 29 January 2017.
- Jules Heller; Nancy G. Heller (19 December 2013). North American Women Artists of the Twentieth Century: A Biographical Dictionary. Routledge. ISBN 978-1-135-63882-5.
- "American University - Corcoran". www.corcoran.org. Retrieved 21 May 2018.
- "A Guide to the Marietta Minnigerode Andrews Papers, 1941-1931". Retrieved 29 January 2017.