MacMillan was born at Kilwinning, North Ayrshire, Scotland. He studied music at the universities of Edinburgh and Durham. He writes a lot of music for the Scottish Chamber Orchestra. They play music at schools so that children can listen and join in with his music.
The Confession of Isobel Gowdie (1990) about a woman who lived in the 1600s. Many people believed in witches then. In 1662 Isobel Gowdie was accused and tried for witchcraft. It was an unusual trial. She confessed without torture, There is no record of an execution. She walked away after confessing.
Veni, veni, Emmanuel (1992) is like a percussion concerto. It is a piece for one percussion player who plays lots of percussion instruments, and an orchestra. The main tune is the medieval hymn tune Veni, veni, Emmanuel (also sung as O come, O come Emmanuel). Scottish percussionist Evelyn Glennie played it at a BBC Prom in 1992.
Quickening is music for a counter-tenor, two tenors, and baritone soloists; children’s choir, mixed choir, and large orchestra. It is about birth and new life. The children’s choir sing the words of the unborn baby. They stand on a balcony or somewhere far away from the other choir and the orchestra. Some of the words are “Glossalalia” (nonsense words). It was performed at a BBC Prom in 1999.