Seán Mac Mathúna was born in Tralee, Co. Kerry. He attended St. Brendan’s, Killarney, and later University College Cork.

Short stories by Mac Mathúna were regularly published in English in The Irish Times, The Irish Press, and in Irish in Comhar. His collection of stories Ding (An Comhlacht Oideachais, 1983) established Mac Mathúna as a gifted writer, remarkable for his anarchic imagination and humour.

The Abbey Theatre produced The Winter Thief/Gadaí Géar na Geamhoíche in 1992, with four nights in English and two in Irish each week with the same cast - a new departure for theatre in Ireland, or in any other country.

In 1999, Banana (Cois Life), his second collection of Irish short stories, appeared. Banana won Gradam Uí Shúilleabháin/Irish Book of the Year 1999. An Taibhdhearc (Theatre) in Galway produced his play Hula Hul in that same year. His novel Scéal Eitleáin was published by Coiscéim in 2005. When Ding and Banana were both out of print, Cois Life published his selected short stories under the title Úlla (Cois Life, 2005), which was subsequently reprinted.

Hula Hul was published in 2007. His best work features on the audiobook Niall Tóibín ag léamh gearrscéalta le Seán Mac Mathúna (Cois Life, 2009).