O’Neill grew up in a largely Irish-speaking rural society in which music, song, and dance were an integral part of life. His maternal grandfather, a latter-day chieftain named Donal O’Mahony, kept open house for travelling musicians; his parents, sisters, and himself, were all great singers; and his parish supported two professional pipers in the years after the Famine. At a young age, Francis began learning the wooden flute, a skill that would help him to read music quite proficiently some years later in America.