Emerging from an earlier piece he wrote for BBC Radio, the work is an anecdotal reminiscence of a Christmas from the viewpoint of a young boy, portraying a nostalgic and simpler time. It is one of Thomas's most popular works.
As with his poetry, A Child's Christmas in Wales uses descriptive passages in a fictionalised autobiographical style, designed to create an emotive sense of the nostalgia Thomas is intending to evoke, remembering a Christmas from the viewpoint of the author as a young boy. Thomas searches for a nostalgic belief in Christmases past - "It was snowing. It was always snowing at Christmas" - furthering his idyllic memory of childhood by describing the snow as being better and more exciting than the snow experienced as an adult. The piece, with exaggerated characters for comedic effect, shows how childhood memories are enlarged through youthful interpretation.