mudie-cooke was born in west london, the younger of two daughters to henry cooke, a carpet merchant, and beatrice mudie. she studied art at st john's wood art school and at goldsmith's college. she also worked in venice for a brief period. in january 1916 mudie-cooke and her elder sister phyllis, who had studied archaeology, went to france as volunteer members of the first aid nursing yeomanry, fany. whilst driving ambulances for fany, and later for a voluntary aid detachment unit, in france between 1916 and 1918, mudie-cooke began to sketch and paint the scenes she saw around her, both among her fellow ambulance drivers and the medical staff they were working with. in particular her watercolours and chalk drawings often focused on wounded troops being evacuated, and the logistics of evacuation such as ambulance trains waiting in sidings. as well as the western front mudie-cooke also served as an ambulance driver in italy during the war. mudie-cooke was fluent in french, italian and german and so sometimes worked as an interpreter for the red cross.