In 1949 Gideon married Brooklyn College assistant professor Frederic Ewen. Both were political leftists. Ewen, who refused to testify before the Rapp-Coudert Committee in 1940, was summoned to testify before the Senate Internal Security Committee chaired by Democratic Senator Pat McCarran in 1952. He retired to avoid testifying. Miriam Gideon was investigated by the FBI, and in 1954 and 1955 she resigned from her music teaching posts at City College and Brooklyn College.^[2]

Gideon composed a lot of vocal music, setting texts by Francis Thompson, Christian Morgenstern, Anne Bradstreet, Norman Rosten, Serafin, Joaquín Quintero and others.^[1] Selected compositions include Lyric Piece for Strings (1942), Mixco (1957), Adon Olom, Fortunato, Sabbath Morning Service, Friday Evening Service, and Of Shadows Numberless (1966).

She was the second woman inducted into American Academy and Institute of Arts and Letters in 1975, following Louise Talma who was inducted in 1974.^[1]

She died in New York City.

Gideon’s 1958 opera Fortunato, edited by Stephanie Jensen-Moulton, was published as part of the Recent Researches in American Music series by A-R Editions in 2013. Jensen-Moulton has published extensively on Gideon, including a number of essays available online, including “Setting an ‘Unused Poem’: Miriam Gideon’s ‘Böhmischer Krystall’ ” for the American Composers Alliance.^[3]