Liam is the youngest, and the last living member, of the Clancy Brothers of Carrick-on-Suir in Co. Tipperary, Ireland.

While still in his teens, Liam explored writing and painting, though he was particularly drawn to the theatre. Before he was twenty years old, Liam had founded the local dramatic society and had produced, directed, set-designed, and starred in J. M. Synge's "The Playboy of the Western World".

In 1955, American song-collector Diane Hamilton Guggenheim arrived at the Clancy home while on a song-collecting tour of Ireland. Liam joined her on her tour and, on a visit to Keady Co. Armagh, they met the singer Sarah Makem and her son Tommy. Both Liam and Tommy emigrated to America the following year, pursuing careers in acting, both on stage and television.

Liam began singing with his brothers at fund-raising events for the Cherry Lane Theatre and at Woody Guthrie benefits. The Clancy Brothers & Tommy Makem, began recording on their own"Tradition" label in the late 50's. A record breaking 16 minute long performance on the Ed Sullivan Show launched the group into stardom. The quartet recorded numerous albums for Columbia Records and enjoyed great success during the 60's folk revival.

In 1973, Liam left the group to pursue a solo career. He moved to Calgary, Alberta, where he became an established television performer. Liam had his own series, which won a Canadian Emmy Award. A guest spot by Tommy Makem on the show led to a reunion with his old pal. As "Makem & Clancy", the two recorded many albums which included several hits such as "The Band Played Waltzing Matilda" and "The Dutchman". They toured and recorded together until the late 80's.

After his brother Tom's death in 1990, Liam joined his brothers Paddy and Bobby and nephew Robbie O'Connell, though he still performed some shows with his Fayerweather Band as well as with the Phil Coulter Orchestra. From 1996-1999, Liam toured with his son, Donal Clancy, and Robbie O'Connell. The group, known as "Clancy O'Connell & Clancy", delighted audiences across North America and Europe. They released two highly praised albums together.

Liam currently performs as a solo act (usually backed by musicians Paul Grant and Kevin Evans and occasionally by Danu) at theatres and festivals across North America, Ireland and Europe. He is completing work on his autobiography as well as a feature documentary directed by award winning director Alan Gilsenen. Liam also runs his own recording studio at his estate in Ring, Co. Waterford where he is currently working on a new album.

At the age of 72 he often quotes Bertolt Brecht's saying, "With a man's dying breath he must be prepared to make a fresh start".