Tom Clancy was a member of the Irish folksinging group the Clancy Brothers. Some may say he had the most powerful voice of the three brothers, a voice he initially used in his earlier career as an actor, appearing in numerous stage productions, including an appearance with Orson Welles in King Lear. Much of his earlier life was entwined with that of his older brother Pat; both men were born in Carrick-on-Suir, County Tipperary, and later served in the RAF during World War II (Tom serving in Europe and North Africa), and were allegedly members of the Irish Republican Army. In 1947 Tom journeyed to Canada with Pat. Together they moved to Cleveland, Ohio to stay with relatives. They attempted to move to California, but their car broke down, and they decided on New York City instead, where the found work as actors. In 1955 their younger brother Liam immigrated to New York, and had met with Tommy Makem. The two began singing together, and were soon joined by Pat and Tom. Thus they formed The Clancy Brothers and Tommy Makem.

The group achieved phenomenal success in America, and they performed together for decades. After splitting and reforming several times, Makem left the group for good, but Tom continued perfoming with the Clancy Brothers until his death in 1990.