His focus for composition for string quartet came in the form of a residency at Princeton University, New Jersey and featured on his first commercial recording, Y=-X2. His film credits include the music to Insight In Mind, The Nuclear Train[2] and The Silent Train, all for Channel 4. His score to Insight In Mind, a short film about mental illness, was screened at the National Film Theatre, London, in 2003.
His first orchestral drama, The Pieta, had its world premiere in St James's Church, Piccadilly, London in May 2009, featuring actor Frances Barber as the narrator with a subsequent cast recording being commercially released through Cayos Records.<ref>The work was revived for a performance at Royal Northern College of Music in 2017
The text and score to his work The Magpie was the inspiration behind the play, Dirty Pretty Secrets, which premiered at the Edinburgh Festival Fringe in 2004.
Cullinan works with his orchestral collective, Tonic Fold, who have released three albums since 2002. They include Numbers Rush By which was released in January 2008 and won the Overplay Songwriters Award 2008 and was shortlisted for the UK Songwriters Awards 2008.