Tom Cullivan was born in the cathedral and county town of Cavan (about 100 km northwest of Dublin in the Irish lakelands) in 1939. He studied piano locally. He began to compose incidental music for the university drama society during his student days at National University of Ireland, Galway (where he took degrees in Celtic Archaeology, History and Law). This led to his involvement with the major theatre companies in the city and he composed extensively for Taibhdhearc na Gaillimhe (the National Theatre of the Irish Language) and for the now world-renowned Druid company, then in its early developmental phase.

Apart from theatre, he has produced an extensive catalogue of compositions embracing all genres, from concertos for piano and for violin to choral cantatas and an opera.

His chamber music catalogue includes, 18 sonatas, 8 of which are for solo piano.

His preference is for the supremacy of melody, straightforward harmony, established patterns of rhythm and form and the concept of music as spontaneous expression. This, together with his background in traditional music and his study of the great collections of ancient Irish music (Bunting, Petrie, Joyce etc.), makes of his own music an attractive fusion of the traditional and the classical, with a distinctly Irish flavour. His music has been performed in Europe and the United States.

He is a former Chairman of the Association of Irish Composers