Ó Catháin was born at Drogheda in 1720, and was taught to play the harp by Cornelius Lyons, harper to the Earl of Antrim.
He then visited France, and went on to Madrid, where he played to the Irish gentlemen living at that court, who praised him to the king.
Sir Alexander MacDonald in Skye gave him a silver harp-key, long in the family, and originally left by his kinsman and fellow harper, Ruaidri Dáll Ó Catháin (died 1653).
O'Kane played all the old native airs, as well as the treble and bass parts of Corelli's correnti in concert with other music.
Had he been but moderately correct in his conduct he might with certainty have raised the character of the wandering minstrel higher than it had stood for a century before."