Ní Dhomhnaill hails from a prominent musical family. An aunt, Neilli, contributed nearly 300 folk songs to the folklore collection of Dublin University. Together with her brother, Mícháel Ó Domhnaill, younger sister Maighread, and multi-instrumentalist Daíthí Sproule, Ní Dhomhnaill first attracted attention with a folk group, Skara Brae, that specialized in songs sung in Gaelic.
When bouzouki player Donal Lunny left the Irish folk-rock band Planxty in 1975 and launched a new record label called Mulligan, one of his first projects was to form a band to accompany accordion player Tony MacMahon on a series of shows for Irish National Radio. Along with uilleann pipe player Paddy Keenan, flute and whistle player Matt Molloy, and fiddle player Paddy Glackin, Ní Dhomhnaill and her brother became charter members. Initially named Seachtar (meaning "seven"), the group changed its name to the Bothy Band after the departure of MacMahon.
As the Bothy Band, the group played their debut concert on February 2, 1975, at Trinity College in Dublin. Although they were only together for three years, Ní Dhomhnaill and the Bothy Band were one of the first bands to bring the musical traditions of Ireland up to contemporary standards. While the group experienced numerous personnel changes, Ní Dhomhnaill and her brother were still members when the Bothy Band's final album, After Hours, was recorded during a concert performance at the Palais des Art in Paris in 1978. A second live album, Live in Concert, recorded by the BBC in London at Pares Theater in July 1976 and Kilburn National Theater in July 1978, was released in 1995.
By the time the Bothy Band disbanded in 1979, Ní Dhomhnaill had been persuaded by singer/songwriter Mike Cross to emigrate to Chapel Hill, NC. Ní Dhomhnaill soon assembled a new band of North American musicians, Touchstone, that initially rehearsed in Cross' home. Touchstone's two albums, The New Land (1982) and Jealousy (1984), combined songs sung in Gaelic, original singer/songwriter tunes, and traditional folk songs from the United States and Nova Scotia.
Relocating to Portland, OR, in the mid-'80s, Ní Dhomhnaill was reunited with her brother, who had emigrated to the area from Ireland a few years before. Together with the Cunningham brothers, Johnny and Phil, formerly with the Scottish group Silly Wizard, they toured and recorded two albums as Relativity. They also collaborated with Phil Cunningham and Brian Dunning, later replaced by Billy Oskay, in a Celtic-tinged new age group, Nightnoise. ~ Craig Harris, Rovi