She was born Amy Marcy Cheney in Henniker, New Hampshire. She made her professional debut in Boston in 1883 and shortly thereafter appeared as a soloist with the Boston Symphony Orchestra. Following her marriage in 1885 to Dr. Henry H.A. Beach, a Boston surgeon, however, she largely stopped performing and devoted herself instead to composition. After her husband died in 1910, she toured Europe as a pianist, playing her own compositions. She returned to America in 1914, where she spent time at the MacDowell Colony in Peterborough, New Hampshire. She died in New York City.
Her compositions include the Gaelic Symphony (1893), the Mass in E flat, a piano concerto, a quantity of choral music, chamber music, and piano music, and the opera Cabildo (1932). She was most popular, however, for her songs.