The life of Dr Mildred Creak spanned almost the whole of the twentieth century (1898–1993) and enormous changes in the understanding of mental disorders and of how children’s wellbeing might be ensured. She made her mark as a psychiatrist despite prevailing prejudices against her sex and she was significant both in establishing the discipline of child psychiatry and for the early history of autism diagnosis. Her life and work intersected with great contemporaries in the field of psychiatry, including notable Quaker psychiatrists who, like her, enlisted during the Second World War. The contribution of Quakers to army psychiatry is relatively undocumented, especially by Quakers themselves. Mildred Creak’s professional life and Quaker commitments intersected too. She was among the group of Quakers that visited Russia in 1951, to much publicity. The author regards her as an unsung twentieth-century Quaker of significance.