Flood was born in Lismore and educated at Mount Melleray and U.C.D. He graduated with a doctorate in music. In 1879 he became organist in Belfast, and in 1895 organist at the Cathedral, Enniscorthy. His 'History of Irish Music' became a university text book. Other works by him include 'The Story of the Harp', 'The Story of Bagpipes', 'The Diocese of Ferns', John Field of Dublin', 'A History of  Enniscorthy', and 'Early Tudor Composers'. In 1922 he was made a Knight of St. Gregory by the pope. He died in Enniscorthy in 1928.