Mountain was born in Shipley, West Yorkshire, and aged 16 he won a scholarship to the Royal Academy of Music, where he studied under the violinist Frederick Grinke.
In 1943 he was conscripted into the Royal Marines Band; in 1945 to 1946 he led a services orchestra on a tour of south-east Asia.
In that year he became head of strings at the Royal Scottish Academy of Music and Drama in Glasgow.
He was chairman of the Scottish Society of Composers; he commissioned works from its members for himself and his wife to play.
[1][2][3] Retiring to West Yorkshire, Mountain became head of strings for Bradford Education.