Emmy Thornam initially took drawing lessons at Teknisk Skole (The Technical School) in Horsens and later on Tegneskolen for Kvinder (The Drawing School for Women) under Vilhelm Kyhn from 1873 to 1875. After having begun her career as a painter of landscapes, she changed her focus to the painting of flowers, a genre, she was able to make a living from. She was educated under O.A. Hermansen and was a student of the painter Pierre Bourgogne in Paris in 1894. Thornam's style changed over time from a traditional more decorative style to a more loose manner with a greater coherence of motif. Emmy Thornam exhibited industriously all her life and was able to suppert her herself through her work as a painter and writer.

As a flower painter, her style shifted over the course of her career from a traditional, more decorative style to a looser approach with greater motivic coherence. Emmy Thornam exhibited extensively throughout her life and made a living as an artist and author. Her memoirs include “Min Søster og jeg” (My Sister and I), which gives a nuanced insight into life as a female artist in the late 19th century.