Born in the Connemara area of County Galway,[1] Breathnach moved to the United Kingdom as a teenager and worked as a DJ at discos in London.
[2] In 1975, he had the lead role in Bob Quinn's first feature Irish-language drama, Caoineadh Airt Uí Laoire.
[7] Other work in television has included the community based programme Eadrainn Féin (1984–1986) and Scaoil Amach an Bobailín with Cynthia Ní Mhurchú (1990–1993).
[2] In February 2007, Breathnach began presenting an hour-long music documentary Siar agus Aniar, on RTÉ Raidió na Gaeltachta.
His twin children Léan and Cárthach Bán Breathnach both had acting roles in the TG4 series Aifric.