As a composer, Simon has created notable works including the Scots Fiddle Concerto and music commissioned for the opening of the new Scottish Parliament. Recent compositions include A' Dol Fodha Na Grèine, premiered at Celtic Connections Festival 2025, the Earl of Louden Fiddle and Cello Duet, and the Iseabail Òg An Òrfhuilt Bhuidhe Cello Sonata.

His collaborations span internationally acclaimed artists such as John McCusker, Dave Milligan, and Ian Carr. He has performed at major festivals worldwide including Celtic Connections and Piping Live, and toured across Scotland, Europe, Canada, USA, Australia and Hong Kong.

Simon’s approach blends traditional Scottish music with contemporary styles. Winner of the BBC Radio 2 Young Traditional Musician Award in 1989, he continues to mentor emerging musicians whilst exploring new possibilities within Celtic music through composition and performance.