Born into a musical family, O’Connell is the third of four sisters. Her mother’s family owns Costello’s fish shop in Ennis where O’Connell works until music becomes her full-time career. She grows up listening to her mother’s light opera, opera, and parlour music records. Her father’s interest leans towards the rebel ballads. Despite the presence of classical music in the house, O’Connell gets very involved in the local folk club scene and together with Mike Hanrahan, who later fronts folk rock outfit Stockton’s Wing, they perform a country music set, as a duo called “Tumbleweed.”
O’Connell attends St. Joseph’s Secondary School in Spanish Point from 1971 to 1974, where she takes part in the school choir. She is also a member of the “Cúl Aodha Choir”, led by Peader Ó Riada, that sings at the funeral of Willie Clancy in 1973.
O’Connell begins her professional musical journey during a six-week tour of the United States in 1980, as vocalist for the traditionally-based Celtic group De Dannan. The following year, she is featured on the band’s landmark album, The Star Spangled Molly, which becomes something of a national phenomenon in her homeland. However, not long after joining the group she becomes very interested in the experimental roots music of America’s New Grass Revival when the bands’ paths cross. She moves to the United States in 1986, settling in Nashville, Tennessee. There she meets progressive bluegrass pioneers Béla Fleck and Jerry Douglas, with whom she works on most of her records.
O’Connell records her first solo album in 1983, however, it does not make any impact in Ireland or in the United States. She receives a Grammy Award nomination for her 1989 album, Helpless Heart, which is her first record released under Warner Bros. Records. Real Life Story (1990) and Blue is the Colour of Hope (1992) register a move toward a pop synthesis. Her versions of “Living in These Troubled Times” and Cheryl Wheeler‘s “Summerfly” become standout tracks on the 1993 album A Woman’s Heart, on four all-female overseas tours and on the 1994 follow-up album in her homeland. A Woman’s Heart Vol. 2 features her heartfelt renditions of Nanci Griffith‘s “Trouble in the Fields” and Gerry O’Beirne’s “Western Highway.” After numerous albums heavily inspired by American newgrass music, she returns to her Irish roots with the 1997 release Wandering Home.
Whelan is best known for composing a piece for the interval of the 1994 Eurovision Song Contest. The result, Riverdance, is a seven-minute display of traditional Irish dancing that becomes a full-length stage production and spawns a worldwide craze for Irish dancing and Celtic music and also wins him a Grammy Award. It is released as a single in the United Kingdom in 1994, credited to “Bill Whelan and Anúna featuring the RTÉ Concert Orchestra.” It reaches number 9 and stays in the charts for 16 weeks. The album of the same title reaches number 31 in the album charts in 1995. He also composes a symphonic suite version of Riverdance, with its premiere performed by the Ulster Orchestra on BBC Radio 3 in August 2014.