In addition to singing and storytelling, Clancy played the harmonica with the group, which is widely credited with popularizing Irish traditional music in the United States and revitalizing it in Ireland.

During World War II he served as a flight engineer in the Royal Air Force in India; he also reportedly had been a member of the Irish Republican Army.

In addition to appearing in various Off-Broadway productions and television shows, they produced and starred in plays at the Cherry Lane Theatre in Greenwich Village and at a playhouse in Martha's Vineyard.

[9] After losing money on some unsuccessful plays, the brothers began singing concerts of folk songs after their evening acting jobs were over.

Paddy and Tom were often joined by other prominent folk singers of the day, including Pete Seeger, Woody Guthrie, and Jean Ritchie.

[10] In 1956 their younger brother Liam Clancy immigrated to New York, where he teamed up with Tommy Makem, whom he had met while collecting folk songs in Ireland.

While still president of Tradition Records, he went as a cameraman on an expedition to Venezuela in search of alluvial diamonds, ostensibly as part of a documentary crew.

The group garnered nationwide fame in the United States after an appearance on The Ed Sullivan Show, which led to a contract with Columbia Records in 1961.

In a 2008 documentary, The Yellow Bittern, Liam Clancy recalled Paddy as the "alpha male" of the group, who "quietly laid down the law" that his younger brothers and Makem followed "without questioning his authority.

[citation needed] After two decades in North America, in 1968 Clancy returned to live in Carrick-on-Suir, where he had bought a dairy farm and bred exotic cattle.