She gained prominence as a teacher, serving on the faculty of Washington Square College of New York University, where she taught music history and composition from 1926 to 1951.
Bauer additionally held leadership roles in both the League of Composers and the Society for the Publication of American Music as a board member and secretary, respectively.
[6] Upon completion of secondary school, Bauer joined her sister Emilie in New York City in order to begin focusing on a career in composition.
[7] In 1905, her studies brought her into contact with French violinist and pianist Raoul Pugno, who was using New York as a base on an extended concert tour of the United States.
[9] (Ultimately, Boulanger would teach such notable figures as Aaron Copland, David Diamond, Roy Harris and Gail Kubik.)
[9] When she returned to New York in 1907, Bauer continued her studies with Heffley and Walter Henry Rothwell,[10] additionally teaching piano and music theory on her own.
[6] Although active as a composer and private instructor in the years following 1912, Bauer ultimately undertook two more periods of study in Europe, partially facilitated by financial inheritances upon the deaths her mother and older brother.
[12] Almost ten years later, Bauer decided once again to undertake an extended period of study in Europe, this time at the Paris Conservatory with André Gedalge, who had also taught composers such as Maurice Ravel, Darius Milhaud, and Arthur Honegger.
[13] During her tenure at NYU from 1926 to 1951, Bauer taught classes in composition, form and analysis, aesthetics and criticism, and music history and appreciation,[13] earning the rank of associate professor in 1930.
[14] Some of her most famous students from her years at NYU included Milton Babbitt, Julia Frances Smith, Miriam Gideon, and conductor Maurice Peress.
[6] During the Great Depression years, Bauer also spent summers teaching at Mills College, the Carnegie Institute, and the Cincinnati Conservatory of Music as well as Juilliard.
Between 1919 and 1944, she spent a total of twelve summers in residence at the MacDowell Colony, where she met composers such as Ruth Crawford Seeger and Amy Beach and focused on composition.
[23] Three days later, on August 9, 1955, while vacationing at the home of Harrison Potter and his wife in South Hadley, Massachusetts, Bauer died of a heart attack, just shy of her 73rd birthday.
[10] For the remainder of her career, though, Bauer continued to integrate both the romanticism advocated by her German teachers with the impressionism she encountered in Paris and in the music of her close friend Charles Tomlinson Griffes.
[26] The influence of the latter is particularly evident in comparing Bauer's 1917 work Three Impressions for piano to Griffes's Roman Sketches published a year earlier: each is an impressionistic-style suite with a poem preceding each movement.
[12] In 1915 and 1916, respected opera singers May Dearborn-Schwab, Mary Jordan, and Elsa Alves were featured on two all-Bauer programs presented in New York, accompanied by Bauer herself.
[33] Notably, Bauer was the second woman to have her work performed by the New York Philharmonic: Leopold Stokowski conducted the premiere of her Sun Splendor at Carnegie Hall in 1947.
[10] Despite this high-profile exposure, though, Sun Splendor was never published in any of its forms–as a piano solo, duet, or orchestral piece–and the only recording currently available is that of the original performance, housed in the New York Philharmonic Archives.
[23] An event Bauer herself considered one of the highlights of her entire career was the May 8, 1951 New York Town Hall concert devoted exclusively to her music.
[23] The concert was reviewed by Olin Downes of the New York Times, who wrote positively of the event : "The music is prevailingly contrapuntal and dissonance is not absent.
As musicologist Susan Pickett points out regarding How Music Grew: From Prehistoric Times to the Present Day, "[T]oday's reader would take offense with several vulgar racial stereotypes.
"[35] Indeed, in 1975, Ruth Zinar published an article surveying racial stereotypes in music books recommended for children, and reserved her most stinging criticism for Bauer's work: "Of all the books studied, Marion Bauer's and Ethel Peyser's How Music Grew from Prehistoric Times to the Present Day must be considered to be the most overtly offensive, in addition to be replete with inaccuracies.
[23] Milton Babbitt also recalls in his introduction to the 1978 edition of Twentieth Century Music how he and his classmates referred to Bauer "not derisively but affectionately" as 'Aunt Marion' for her matronly manner and appearance, and even for her classes, which were conducted so as to be suitable for occurrence at teatime in a genteel parlor.
[44] Although unconfirmed, Ruth Crawford Seeger's writings, when considered along with remarks by Martin Bernstein (a longtime friend of Bauer's and a former chair of NYU music dept.)
[45] Bauer's legacy can be measured not only by her output of at least 160 compositions along with her five books,[51] but also by the impact she had on the careers of both Ruth Crawford Seeger and Milton Babbitt, who went on to become well-known American composers of the twentieth century.