[3][4] His maternal grandparents were Pádraig Ó hUallacháin, a teacher, writer and song collector, and Eithne bean Uí Uallacháin.

In 2003, O'Connor featured on New Irish Hymns (released as In Christ Alone in the United States) by Moya Brennan, Margaret Becker and Joanne Hogg with compositions by Keith Getty[7] and in the summer of that year presented the BBC Radio Ulster programme Cualán.

O'Connor acted as music teaching consultant on the 2003 film, The Boys and Girl from County Clare, directed by John Irvin and starring Andrea Corr, Colm Meaney and Bernard Hill.

He again in 2004 featured on Irish-language television station TG4's broadcast of Sé Mo Laoch, that year focussing on the life and work of his paternal grandmother Rose O'Connor.

In 2008, O'Connor was commissioned to compose idents for BBC Radio Ulster's Irish language department whilst also touring extensively, including performances at Temple Bar TradFest,[17] Return to Camden Town and William Kennedy International Piping Festival.

Gort na Glaise was performed as part of the Drogheda Traditional Music weekend alongside Neil Martin and Michael McCague in an event also featuring writer and climber Dermot Somers.

[20] O'Connor was also commissioned that year by The Armagh Pipers Club to arrange and orchestrate a number of traditional tunes to be performed by an Uilleann pipe orchestra of 45 players.

[21] O'Connor produced, arranged and played on Belfast singer Gráinne Holland's debut album, Teanga na nGael, released in August 2011.

A hefty touring schedule ensued and the trio have since collaborated with Mary Dillon of Deanta, Liam Ó Maonlaí Hothouse Flowers, Ríoghnach Connolly, and Muireann Nic Amhlaoibh formerly of Danú.