He had the most powerful voice of the brothers and had previously been an actor in numerous stage productions, appearing with Orson Welles in King Lear.

While in Ireland, Clancy worked for the Shakespeareana Internationale company run by English actor and manager Geoffrey Kendal.

[11] Tom took the lead vocals on many of the group's songs, such as "The Rising of the Moon", "The Moonshiner", "Haul Away Joe", "Red Haired Mary", "The Barnyards of Delgaty", "Carrickfergus", "I Once Loved a Lass", and "The Bold Fenian Men", among others.

Clancy continued to act during his singing career, appearing in the movies The Killer Elite (1975) and Swashbuckler (1976).

[12] After an absence of fifteen years, Clancy returned to Broadway in May 1974 in Eugene O'Neill's A Moon for the Misbegotten.

The Irish Times reviewed his performance of Phil Hogan: "In 'Moon' he deftly measures up to the formidable company in which he finds himself – a wily, sly rogue with a whimsical humour and a genuine concern for his daughter".

Before his marriage to his wife Joan, he had had two children, Eileen and Thomas, with Yvonne Marcus, in Cleveland, Ohio.