Fanny Bré was a volunteer nurse in the International Brigades, who fought in the Spanish Civil War (1936–1939) on the side of the democratically elected Republican government. The objective of this study is to understand the relationship between Bré's antifascist ideas, her conception of care and the activities she carried out in the Spanish hospitals of Casa Roja (Murcia), Villa Paz (Selices, Cuenca) and Vic (Barcelona). We use narrative biography to describe Bré's personal, political and professional trajectory. To do so, we conducted a content analysis of primary sources archived in Spain, Russia and France and secondary sources that emerged from a thorough literature review. We identified three thematic axes: (1) a concept of nursing in the service of the antifascist struggle, (2) nursing activity for high‐quality care and (3) political action for improving hospital organisation and care. The interest of Bré's texts transcends the war in Spain because, in them, Bré questions the neutrality of care by revealing that care can itself be a political act.