Cormac has been playing whistles and the timber flute for nearly 30 years now. He was born in Dublin and was brought up in an Irish and Spanish speaking household. He now concentrates on playing plastic and low (aluminum) whistles. He has recorded extensively with musicians such as Donal Lunny, Maire Breatnach, Steve Cooney and songwriters such as Tom Moore, Sonny Condell, Pierce Turner, Elvis Costello and Maighread Ni Dhomhnaill to name but a few.

He has also featured on award winning TV Programmes such as Bringing it all back Home and The River of Sound. Cormac's playing also featured on the original Riverdance track and he has also recorded for the special production of Lord of the Dance in London, England. His playing can also be heard in movies, such as The Secret of Inish Roan, Moondance and The War of the Buttons.

The Irish Voice (October 1994) described Cormac as The Fresh Prince of Jazzy Jigs, writing "...not the first musician to add modern rhythms and jazzstyle improvisations to Irish traditional music but he has taken the concept further than anybody else."