Ó Raghallaigh spent several summers working part- and full-time in the Irish Traditional Music Archives in Dublin, opening up a wealth of old recordings which influenced his repertoire and style.
Together with uilleann piper Mick O'Brien, he recorded Kitty Lie Over, named no.1 traditional album of 2003 by Earle Hitchner in American newspaper the Irish Echo.
He is a member of two contemporary traditional music groups: The Gloaming (with Martin Hayes, Iarla Ó Lionáird, Dennis Cahill and Thomas Bartlett); and This Is How We Fly (with Petter Berndalen, Nic Gareiss and Seán Mac Erlaine).
Ó Raghallaigh uses crosstunings or scordatura (common in Norwegian and old-time American fiddling), and uses baroque and transitional bows made by Michel Jamonneau.
[5] In 2019, he and fellow Gloaming member Thomas Bartlett released a special self-titled album of studio collaborations the pair had recorded together during gaps in the group's touring schedule.