Edgar Deale was born in Dublin. Apart from sporadic studies with Turner Huggard and W. J. Watson he was self-taught as a composer.
While maintaining a career as a leading insurance manager in Dublin, he wrote some forty original compositions between the 1940s and the late 1970s. These were performed by, among others, the Radio Telefís Éireann orchestras, the Radio Telefís Éireann Singers, the Dublin Orchestral Players, and the Culwick Choral Society and Consort. He also wrote numerous arrangements of Irish traditional songs for choir, many of which were published by Oxford University Press and others. He was a founder member of the Music Association of Ireland and was a prime mover in most of its projects, taking on the editorship, in 1968, of the first published catalogue of the music of twentieth-century Irish composers.