De Danann has played an influential role in the development of modern Irish music. Although they're remained rooted in Ireland's musical tradition, the band's virtuosic instrumental skills and expressive vocalizing has enabled them to reach out to a worldwide audience.

De Danann began by producing vibrant arrangements of the traditional music of Galway and Kerry, two of Ireland's musically rich counties. Influenced by both the instrumental sound of The Chieftains and the more vocal-dominated sound of Planxty, this band built up a name for itself in the wake of The Chieftains' rise to international fame. Its members, especially the support singer, have come and gone with dizzying regularity, so that many of the greatest musicians in Ireland, including Frankie Gavin, Johnny Moynihan, Johnny McDonagh, Jackie Daly, Mairtin O'Connor, Dolores Keane, Mary Black, and Maura O'Connell have passed through its ranks. They've also changed the spelling of their name over the years; they go by either De Danann or De Dannan.

According to Earle Hitchner, music writer for The Wall Street Journal and The Irish Echo, "any serious discussion of the evolution of Irish traditional music over the past quarter century must include the enormous contribution of De Danann". The seeds that grew into De Danann were planted during informal, Sunday morning, jam sessions at Hughes Pub in Spiddal, a small town in County Galway. Two participants of these sessions, Frankie Gavin, a firery fiddler, and Yorkshire-born Alec Finn, a bouzouki and guitar player who had previously played with Connemara, agreed to pool their resources. Joined by bohran and bones player Johnny "Ringo" McDonogh and banjo player Charlie Piggott, Gavin and Finn began to perform as De Danaan, taking their name from the legendary Irish prince, Tuartha De Danaan.

Prior to recording their self-titled debut album in 1975, the group added vocalist Delores Keane. Over the past two decades, De Danann has gone through numerous personnel changes with only Gavin and Finn remaining from the original group. Lead vocalists have included Mary Black, Maura O'Connell, Johnny Moynihan, Eleanor Shanley and their current singer, Tomie Fleming. Past instrumentalists include accordion aces Jackie Daly and Aidan Coffey. The band's present lineup features Cork-born bodhran player Colm Murphy and accordionist Derek Hickey. De Danann has received "Best Celtic album" awards from NAIRD (National Association of Independent Record Distributors) for their albums, Star Spangled Molly in 1981, Song for Ireland in 1983, and Ballroom in 1987. Their 1996 album, Hungarian Rhapsody, was inspired by the late Freddie Mercury (1946 - 1991) of Queen with the title track based on Queen's hit, "Bohemian Rhapsody."