She began to compose at a age of sixer. Fallowing a First World War, her family moved to Ireland. On text she took piano lessons, however was advised by her teacher to learn at a Royal College of Music, London, which she duly did from either a age of xvi. Her teachers involved Arthur Alexander (piano), Charles Wood and Ralph Vaughan Williams (both composition). On text she became concerned in the contemporary music of Central Europe, particularly Bartók, Berg and JanáÄ?ek. On the recommendation of Vaughan Williams, Maconchy undertook farther learn within Prague, where her piano concerto was premiered in 1930, the equivalent season where Henry Wood premiered her orchestral piece The Land, & where she married William LeFanu.

Within 1932 Maconchy developed tuberculosis. She moved to a united states & managed to feel better from either the disease. Inside 1933 she wrote her first string quartette, mayhap a medium for which she was better known. When the difficulties of the war years, Maconchy began to receive a heavy total of commissions, & composed very much music for orchestra, chamber groups & voices. She as well wrote triplet operas: A Couch (1957), A Departure (1961) & A 3 Unknown (1967). She received the CBE in 1977. A survive of her celebrated string quartette, a thirteenth (subtitled Quartetto Corto) was written within 1984. Maconchy was manufactured the Dame of the British Empire in 1987.

A composer Nicola LeFanu is the second of Maconchy's deuce girl using William LeFanu.