Allen first became interested in children’s books while teaching kindergarten in Toronto schools, which he did from 1974 to 1980. Many of the ideas for his picture books grew out of day-to-day contact with young children. He has also written short stories for older readers.
Allen has been writing children’s books full-time since 1980. Each year he spends a number of weeks touring schools and libraries as a storyteller to young children.
Allen lives in Toronto with his wife, Leslie.