Hayes was born into a musical family in Maghera, a townland in the parish of Killanena in East County Clare, Ireland.

[2] To make a living he worked in bars playing in a variety of genres including "rebel music, and songs and stage Irish humor in clubs, and all kinds of things".

[6] In 1989 he and the Chicago guitarist Dennis Cahill formed "Midnight Court", which combined traditional Irish and rock music.

[7] In 1996 Hayes formed an acoustic duo with Dennis Cahill, developing an "unrushed, lyrical, highly expressive interpretation" of traditional Irish music.

[2] In 1999 a New York Times reviewer described Hayes and Cahill's approach as "stripping old reels and jigs to their essence, leaving space between the notes for harmonics and whispered blue notes," resulting in "a Celtic complement to Steve Reich's quartets or Miles Davis's Sketches of Spain.

"[8] Hayes and Cahill have released three recordings on the Green Linnet label: The Lonesome Touch (1997), Live in Seattle (1999), and Welcome Here Again (2008).

[11] Since 2019 he has performed with the Common Ground Ensemble, a specially formed group including Cormac McCarthy on piano, Kate Ellis (of Crash Ensemble) on cello, Kyle Sanna (of Brooklyn Rider) on guitar, and Brian Donnellan (of The Tulla Céilí Band) on bouzouki, harmonium and concertina.