He was the brother of Rodolfo Halffter and part of the Grupo de los Ocho (English: Group of Eight), which formed a sub-set of the Generation of '27.
He wrote his earliest composition at the age of six, and in 1922 his piano teacher Fernando Ember performed three pieces from Crepúsculos at the Ritz Hotel in Madrid.
In 1934 Halffter became director and conductor of the Seville Conservatory of Music but, being married to the Portuguese pianist Alice Câmara Santos, chose to live in Lisbon during this period up to 1954.
[3] When Falla died in 1946, he left his opera Atlántida incomplete; Ernesto Halffter was asked to complete it.
Halffter was a personal friend of Salvador Dalí, and was asked to write a piece of music to celebrate the event.