[citation needed] Ó Gallchobhair was a prolific composer and arranger of Irish traditional music for a wide range of instrumentations.
Between 1935 and 1942 he wrote eleven "Dance Dramas", ballets on folklore themes, with one of the latter commissioned by Joan Denise Moriarty.
He also wrote five light operas, or operettas, on Irish (Gaelic) texts, between 1944 and 1963, including Nocturne sa chearnóg (1942), Trágadh na Taoide (1950), Íoc-shláinte an ghrá (1954) and An mhaighdean mhara (1960).
[5] Ó Gallchobhair was a major representative of the conservative side in Irish twentieth-century art music.
[6] With this position he stood in stark contrast to contemporary Irish composers such as Aloys Fleischmann, Frederick May, or Brian Boydell.