Thomas Patrick McKenna was born at Mullagh, County Cavan, Ireland, in 1929 and educated at Mullagh School and St Patrick's College, Cavan. He was the eldest of ten children of Raphael McKenna, an auctioneer and merchant, and his wife Mae. There he became a protégé of Fr. Vincent Kennedy, who featured him in the annual productions of Gilbert & Sullivan operas. He was a noted treble and sang in Cavan Cathedral, but later would also become a keen member of the school's Gaelic Football squad, representing St Patrick's in the final of the All Ireland colleges competition in 1948.
