In the early eighties, he discovered Bluegrass and spent four years as fiddler with the Sackville String Band, the popular Dublin outfit that played at concerts and festivals all over the country.

Influenced by the recordings of the Fuzzy Mountain, Hollow Rock, and Highwoods String Bands they played "American traditional music, old-time songs and bluegrass".

The band's reputation was such that many visiting U.S. musicians would jam on stage with them and so Kelly got to hear and play with Bluegrass legends like Peter Rowan, Tex Logan and Kenny Baker.

They also supported The Pogues (who were riding high on the success of Fairytale of New York), on the English and Irish leg of their world tour.

In March 1992, after he had established himself as a studio session musician, and had composed the music for the Irish movie, Hard Shoulder,[9] Kelly returned to his traditional roots by joining with Trevor Hutchinson and Gerry O'Beirne in The Sharon Shannon Band.