Niall studied piano and composition at the Royal Irish Academy of Music. He was awarded first prize at the 1992 Dublin film festival's Music awards, chaired by English composer and critic Michael Nyman. Since then Niall has composed music for feature films, animation and many critically acclaimed and award-winning British television drama series including 'The Widower', 'Cilla' and 'Little Boy Blue'. His many international film score credits include the psychological thriller 'In Darkness' starring Natalie Dormer. Recent television dramas include the ITV drama series 'White House Farm', 'A Confession' starring Martin Freeman and written by Jeff Pope (Oscar-nominated writer of Philomena, Stan and Ollie) and the critically acclaimed drama series 'Manhunt' starring Martin Clunes. 'Manhunt' premiered in January 2019 and was ITV's highest rated new drama since the launch of 'Broadchurch'.
Niall has received five IFTA (Irish Film & Television Awards) nominations and won the award for his score to the BBC film 'Loving Miss Hatto', starring Francesca Annis and Alfred Molina, which told the story of concert pianist Joyce Hatto. In 2017 he received the Venus award at the Badalona Film Festival in Barcelona. His score for the animation series 'Peek Zoo' was nominated for Best Score at the 2019 Irish Animation Awards.
His orchestral score for the classic Irish silent film 'Guests of the Nation', which was commissioned by the Irish Film Institute, has been performed by the RTE Concert Orchestra in Dublin (National Concert Hall), London (Barbican Centre) and New York (Alice Tully Hall, Lincoln Center). He has received awards from the Irish Arts council, one of which included a series of seminars on film music by Ennio Morricone at the Chigiana Music school in Sienna.
In his spare time Niall composes music for personal projects, usually involving piano. Niall has released three solo piano albums. Two of these, 'The Promenade' and 'Still Life', were released by the contemporary classical label '1631 Recordings'. His third piano album 'Nightsongs' was released independently. In 2019 Niall signed with publisher Faber Music in London.